Without repeating all the stuff on the post about "Marine Brass?" the subject of TONVAL has not been addressed and perhaps should be. Many suppliers are selling skin fittings and valves in this material and the implication is that it is suitable for underwater use. My question is simply this.... Does ANYONE know what it is? I mean specifically? What is its chemical composition? Where does the term come from? Has anyone seen any test data on it or have any reason to believe it is suitable and will resist dezincification? Or are we all just accepting the publicity without question?
Nothing to add that isn't already in the 'Marine Brass' thread, but as boatmike suggests, this is IMPORTANT. Somebody out there must know. But if they don't...well, QED, the stuff's a pig in a poke
Don't know the composition - Tonval ATD is a corrision resistant but may suffer from dezincafication. It is perfectly suited for above the water line and many yachts have it below the waterline without any problems.
Your statement should read "without any problems YET!
These components are safety critical, its like bunjee jumping on knicker elastic.
As it breaks you hear the protest..... I NEVER HAD THIS PROBLEM BEFORE !!!!!>>>>>
10 years and counting... Hammer test every year. The point was made on the other thread it depends on the stray currents around - no problem on a swinging mooring, bit of an issue in a marina.
Anyway don't you have hard wood bungs next to the skin fittings - I do even where I have LG2 fittings for the heads!
There is a risk with Tonval but if inspected it is manageable.
PS My Asap catalogue quite clearly states at the top of pages on pipe fittings that it is only corrosion resisting. The problem often is that for pipe fittings you can really struggle to find some combinations in anything else
If you have HARDWOOD bungs probably best to throw them away and replace with softwood bungs which will shape themselves to fit the hole when hammered in rather than splitting it open .
Bungs are really a case of"drinking in the last chance saloon".By the time you locate the correct failed skinfitting or seacock the water is going to be rising fast.
I was on a motorboat where an almost new seacock sheared off due to poor design/installation .Only the fact that it was plumbed in with rigid piework which held it in place .Coupled with better bilge pumps than you will find on 95 /100 boats saved us from some liferaft practice. Wind gusting to 70 knots at the time.
"Tonval ATD: The trade name given to the 60/40 leaded brass used in themanufacture of through-hull fittings. The closest ISO material designation is CW619N and the material symbol designation is CuZn40Pb2Sn.
CW619N: A brass suitable for wrought and unwrought forging with the composition: copper 57-59%; aluminium 0-0.1%; Iron 0-0.4%; Nickel 0-0.3%; lead 1.6-2.5%; tin 0.2-0.5%; remainder zinc (approx. 38-40%).
The trade name Tonval, in the UK, conceals rather than conveys the nature of the material used for the through-hull fittings. To ensure that buyers of these products are fully aware of the nature of the material, such fittings should be clearly described as made of a “brass (not inhibited against dezincification)”."
If that's the case Roberto my suspicions are verified. Thanks for the information. Retailers (and there are many) who describe this material as Tonval Bronze are telling lies. It definitely ain't bronze and if, as you say, it is a brass that is not even inhibited against "de-zincing" should, as I originally thought, never be fitted below the waterline.
As luck would have it my new ASAP catalogue just came through the door. In it there are through hull fittings in Gunmetal (excellent) Perko (trade name) fittings in what are called "cast bronze" (lord knows what sort though) 316 stainless steel ones. (should NEVER be fitted below the waterline in my opinion) and guess what? What they call TONVAL BRONZE ones! There are also other fittings such as hose tails that are Lloyds approved in DZR and TONVAL BRONZE ones too. So it's obvious to me that we should NEVER fit tonval anywhere on the boat that comes into contact with seawater. It's also evident that GUNMETAL fittings are still widely available and should be used for this purpose.
I just had a saved copy of the report, I found the <A target="_blank" HREF=http://www.dft.gov.uk/stellent/groups/dft_maritimesafety/documents/page/dft_masafety_027359.pdf>original one here </A> anyway
My ASAP catalogue(7th Edition) has the note:-
"Tonval ATD - Has corrosion resistance but is susceptable to dezinctification. Bronze UNI 7.13/8 G-CuSn5ZnSPs - Frequently known as Gunmetal" But no spefic recommendation as to where they should be correctly used.
BUT this note is on the Seaflow Pipe Fitting page, which is 2 pages AFTER the 'Through Hull Fittings/Seaflow Hose Tail Fittings' pages. There should be a definate note concerning Tonval ATD such as "Tonval ATD must NEVER be used underwater"
<hr width=100% size=1>dickh
I'd rather be sailing... :-) [img]/forums/images/icons/smile.gif[/img]
__________________
dickh
I'd rather be sailing... :-) [img]/forums/images/graemlins/smile.gif[/img]
As you mentioned our catalogue by name, we thought we ought to add our comments.
We have been selling these fittings for 16 years now. They have been on the market for much longer than that. We have chosen all our underwater fittings from the best suppliers we can find. Almost all our Tonval and Gunmetal items are made by Guidi (Italy) and Perko (USA). We have not chosen for lowest price, we have chosen for quality. Our Perko gunmetal valves are probably the most expensive in the UK - but they are UL Listed, and approved by the US Coastguard for use as underwater through hull fittings. Page 52 of the 7th edition, bottom LH corner has a seacock to beat most of them. The only problem is, NPT threads (UK is mostly BSP) and price. Most people don't want to pay over £50.00+VAT. However, even our less expensive general gunmetal and DZR fittings/valves are chosen for quality and not low price. We always recommend them as the minimum for salt water applications, and have been selling for 12+ years.
Then we have the cause of the post - Tonval ATD. This is a type of brass, however, in the case of Guidi fittings, it is a good quality. We have sold this since we started, and inland boats on fresh water (eg Norfolk Broads) have used these fittings through hull for years before we started, without problems of any sort. There are certainly different grades of material with the same name, but we can assure people, that the cheap stuff ain't coming out of this of warehouse. We publish all the specs we have - we are not trying to disguise cheap brass with a fancy name - Tonval is a specific name - and that's what we sell and have sold since we started.
The problem with ALL of this is not generally the fittings. It is the application of them. The fittings have not changed for years. It is people - many want to build boats for a budget, and through hull fittings can't be seen. People can't show off their 'top of the range' seacock, so the money goes else where. Sorry, but that's the case for many. Boating ain't cheap - let's save a quid and get the fittings at the local boat jumble! Thankfully many are now realising that you don't get something for nothing, and are willing to pay a bit extra for the better materials. They are generally more expensive because they contain more of the metals that make them corrosion resistant - and those metals are expensive!
The comments by 'salamicollie' are some of the best on this string. For certain boats, Tonval is fine, for others not, and mostly the problems with the 'nots' will be down the galvanic action due to marina moarings or incorrectly placed/lack of Anodes. Make sure the anode is in sight of the through hull fitting. Make sure they are all bonded. Check anodes regularly and replace often Visit the MG Duff site - ask for a brochure. They give advice freely, and their high quality anodes are available almost everywhere (as well as from us)
Lastly 'Stainless 316' These fittings are relatively new to the market. Again, for certain vessels they are fine - and can be fitted as underwater fittings. After all, if stainless 316 should not be used, what's the point of making them - and 95% + of you have a stainless 316 propshaft I wager! They should always be assembled completetly 'dry' ie no water or damp around at all. They should NOT be used on a wooden boat. The reason is a complex one, and due to the new nature of the product, is still subject to debate, but stainless 316 needs oxygenated water to form a protective barrier. If this barrier does not form, then the fittings can corrode.
So, if you use the ASAP catalogue, we would like to point out that we have tried extremely hard to offer the very best fittings on the market. We have always tried to offer products that we sell, you fit, and then we all forget (but remember to check!!) We cannot publish specific recommendations for these products - it is such a vast and complex subject. We have a huge water network, and fittings that have lasted for years on a boat moored at point A, may corrode away to nothing in a month when the boat is moved to point B.
They best advise we can offer, is to check, check and double check. If the boat is going into salt water - fit the very best. Don't skimp, especially if you plan to keep and use the boat. If you save a few quid - get two sets - chances are you will need them!!!
Disclaimer. This is not intended to be a sales pitch for ASAP Supplies. Yes, we offer a good range of quality products, but so do many other marine retailers and wholesalers. There are a small few who offer product of a lower grade, but generally the marine trade wants you all to have good experiences when boating and to enjoy yourselves. Maintenance is a pain we know. Most of us offer products that let you enjoy boating. How much you want to pay is up to you.
We do sincerely hope this helps. If you need any other advice or information, please phone and we will try to help as best we possibly can.
Well - here is one very satisfied customer - when we ordered an incorrect match of products for water intake (over the internet) we had a phone call asking us about the application and if that is _really_ what we wanted ... great advice ... great prices
PS do I get a discount now?! [img]/forums/images/icons/smile.gif[/img]
<hr width=100% size=1>
__________________
Bavaria keels don't fall off, they just wobble slightly.
You have chosen to take the criticism of Tonval as a general criticism of ASAP Supplies Ltd. Let me therefore start by saying that I have used ASAP supplies both privately and professionally for a number of years and have found your staff and service extremely efficient and courteous. However I believe you do yourself a dis-service with many of your remarks which seem to be aimed at defending ASAP rather than addressing the issue which should concern you as much as your customers to whom you owe a duty of care.
Let me therefore take your points in order.
1. I have no doubt that your gunmetal valves etc are of good quality and have accepted your word that they are in fact what you represent them to be. Genuine Gunmetal. In fact I have fitted your gunmetal fittings not only to my own vessel but many others in a professional capacity. I have no doubt as to the honesty of your intentions. My first and main contention (on another thread) was that gunmetal fittings should be fitted below the waterline in preference to anything else. I remain of that opinion. I would suggest that in fact, to promote the use of these superior fittings you should advertise the endorsement of USCG, Lloyds, DNV or anyone else as applicable. I see no reference to this in your catalogue apart from one or two items which are Lloyds approved. This leaves the majority of your customers legitimately assuming that the others are not approved at all. Incidentally I would point out that on page 50 you confuse the issue further by stating that your Standard range of gunmetal through hull fittings are "shell moulded in tonval" this is obviously a mistake but hardly helps your case.
2. Why, if you recognise Tonval as being a type of BRASS, do you insist on designating it as Tonval BRONZE? It clearly is not only a brass but one with NO RESISTANCE TO DE-ZINCIFICATION and therefore inferior to DZR not to mention "true" bronze. You do not seem to dispute this fact so why not say it? You say you are not trying to disguise cheap brass with a fancy name. YES YOU ARE!!!! You are calling it BRONZE!!! It is not bronze. Bronze is a Copper Tin alloy. Brass is a Copper Zinc alloy. Certain types of zinc based alloy, while inferior to gunmetal (which is a true bronze) are formulated to resist de-zincification in salt water and are therefore acceptable. Others like Tonval are not and should never be fitted below the waterline on a seagoing vessel.
Rattling on about how many FRESH WATER boats on the Norfolk Broads have been fitting them for years is not only irrelevant, it is seeking to suggest that they are good for seagoing use and they patently are not. Not one of the classification societies will accept them as being so and as a professional Marine Engineer neither will I!
3. Your diatribe regarding people wanting cheap "boat jumble" bits is entirely misplaced. If the majority of amateur boat owners buy on the cheap, which I am afraid is certainly true, one should perhaps ask why? I would contend that it is mainly out of ignorance rather than design and not helped by a complete lack of information from the trade. If you want to hold ASAP up as an example of a quality supplier, which I think indeed you should as I am not dissatisfied regarding your products or services generally, you should in fact endorse the use of quality fittings, make it clear to your customers that you recommend their use, and try to educate them. I do not in fact object to you selling fittings in non DZR brass but believe you should make it clear what they are and not misrepresent them as BRONZE.
4. You say you publish all the specs of the items you sell.
Perhaps you would be good enough therefore to tell this forum what class of bronze is used for the PERKO range and GUIDI range? In some parts of your catalogue you have called the item "cast bronze". In your reply to this forum you have indicated that they are gunmetal bronze. Are they? Or are they in fact Manganese Bronze (which is another form of brass missnamed as bronze)? Or are they perhaps Aluminium Bronze, or Phosphor Bronze? Please don't think I am being deliberately rude, as it is not my intention to be so, but as retailers rather than manufacturers do you in fact know the difference? Or are you in fact, as I suspect, just repeating the manufacturers blurb verbatim and in the same boat as the rest of us in not having the slightest clue what the damn things are really made of in the first place other than a general generic description that tells us very little?
5. Stainless steel underwater is as you say a complex subject. On another forum you will find that I have taken a general view that 316 should preferably not be used below the waterline. I have also conceded elsewhere that there are many 316 propshafts about. Most of them, usually around the area of the shaft seal or inner bearing will exhibit some form of hydrogen embrittlement or crevice corrosion in time though and it is hardly the material of choice. A better material again is bronze with monel as a close second. Both these materials are in fact expensive and 316 is servicable enough as long as the owner is aware of the limitations and periodic inspections are carried out.
I have no intention for professional reasons of entering into a specific debate with you on open forum regarding the products of a particular supplier. I would however reiterate that I would never recommend the fitment of stainless steel fittings of any sort to the underwater sections of a seagoing vessel especially when there are many other viable alternatives.
Finally therefore may I end as I began by saying that I have used ASAP for almost as long as you have been in existence and am very happy with your service. I believe you try your best to give good advice and usually back up your products with information where called for. I do not expect you to become a free consultancy to the industry however and you are correct to point out that your customer base is both diverse and varied. What I do expect from you is that you are concise and accurate in your representation of what it is that you sell. There is clearly a need here to add a little value by supplying more detailed and accurate information.
What I think would impress me more than your current reply would be a clear answer to the questions I have asked you regarding the specific materials that your products are made of. "Cast bronze" and "Tonvil Bronze" should in fact be recognised as at best uninformative terms and at worst downright misleading.
Some statement to indicate that you will make some effort to be more correct in your description when the 8th edition of your catalog comes out would in fact be impressive and give you a further competitive lead in the marketplace. You have shown enough interest to become involved in the debate which I applaud. If you would now correct the errors suggested and illustrate your real interest by publishing the material specs involved as asked I believe we would all be grateful and truly impressed.
At no point did A.S.A.P. Supplies Ltd feel critercised. We merely saw our name mentioned, and thought we could help. Our reply was not intended to be defensive or to open a can of worms. It was infact passed round the office in order to ensure there were no offending or misleading statements in it. It seems our best intentions could have, in some eyes, been better. Apologies - no misleading intended what so ever.
As for specs in the catalogue. Unfortunately we have no more space in the 8th to add more than in the 7th. but.........
....... to correct......
We apologise that we don't respond to the forum questions on a next day basis, but we WILL ensure we get together all the specs of the items in question and let you know. We will also make sure that we add the answers to our FAQ page on our website. That way we will have at least provided the answer to your original question - better than we did at the first attempt. This info won't appear overnight as we will double check the suppliers to make sure the specs are exact.
We hope this will go towards showing that constructive critercism is always welcome, and if it is possible to do something better - then we will.
Thanks for the reply, albeit an understandably interim one as you need your suppliers input before responding further I guess. But thanks for "hanging in there"
I am glad you have responded positively as I have no contest with ASAP as I said before, and if you can manage to get more information on the materials used by the manufacturers it will show an interest not shared by other retailers and reinforce my faith in you!
May I say that I have just placed an order with you for a number of items, and included in them are a whole load of "Tonval" fittings which I intend to use to connect my Eberspacher water heater and engine to my calorifier with so this illustrates that not only do brass fittings have a place in the scheme of things but I am happy to use them on a fresh water plumbing job myself!
No. Far from criticising ASAP, the original point was that the end user, represented by the ordinary blokes on this forum need to know what materials are used in order to make a valued judgement when fitting stuff to their boats. There are no text books I know of or internet sites that I have visited that actually tell me what tonval is. With great respect I think your catalogue should not refer to it as bronze and even the term ATD used elsewhere in your catalogue means very little to me as I don't know what ATD stands for! I feel somewhat like the little boy stood up in front of the Emperors coach in Hans Andersons tale.... ASAP are clearly not the only ones to have called tonval "bronze". Lots of people have and still do. You however, unlike some others, in addition to Tonval, list Gunmetal and other bronze fittings. It's only a thought but if you made it clear what the difference was in your catalogue I believe more people would be convinced to buy the more expensive kit where its application is justified and you would make more profit! So we are not coming at this from different angles at all. You can benefit!
As a chartered engineer, I have some knowledge of materials, but am not a metallurgist and don't know everything. There are several things I am sure of though which might be useful for you to consider.
True bronze is an alloy of mainly tin and copper. Gunmetal is a true bronze.
Manganese bronze is a missnamed alloy that contains zinc. It is therefore not a true bronze as gunmetal is. There are however forms of manganese bronze that are alloyed to resist de-zincification in sea water. These are very useful and applicable alloys because they have extremely high tensile strength and can be cast easily. Most "bronze" props are manganese bronze in fact for these reasons but they are not truly bronze at all. They are brass. Brass is primarily a copper zinc alloy. But we all know and accept that DZR forms of manganese bronze are "kosher" for use underwater in a seagoing boat. Likewise, there are other forms of brass, less sophisticated than manganese bronze that don't have this high tensile advantage but are still DZR and will resist de-zincification in seawater. That's why Lloyds approve them. Then there are the common brasses that are not DZR which we believe tonval to be a variety of. These are simply brass. Then there are other alloys which I won't confuse the issue with.
All we really need to know is which is which.
Then there is the question of bonding. Bonding fittings to an anode is an attempt to ensure that any electrolytic de-composition is concentrated at the point of the anode itself not the fitting. A good idea in relation to propellors etc. made out of DZR material but not such a good idea if the fitting has a high content of unprotected zinc. In fact what is possibly going to happen if you connect a brass fitting to the bonded circuit is that the fitting itself could become the anode and fizz away in a very short time! So please don't advise people to bond tonval to their anodes. It could be disasterous.... In fact there are lots of differing opinions regarding bonding skin fittings, but I believe that if they are made out of gunmetal they should not be bonded. I have personally never bonded gunmetal fittings to the anode but sometimes they are inadvertently bonded through say the steel reinforcement of the plastic hose that connects the skin fitting to the engine....
See how complex this can get? However, Gunmetal, having no zinc content cannot de-zinc anyway so is not at risk either way.
Hope this helps and that the further information promised will be forthcoming from your suppliers. Look forward to the details if and when!
In the mean time MERRY CHRISTMAS to all at ASAP supplies and thanks for all the help you have given me throughout the year.
Hello.
With Christmas and the London Show out of the way, we can make headway on this task. We are in the process of building the new page on our site with all the material specs as promised. We have a few blanks in the database, but it's getting there. In the meantime, back to the original question - What the hell is TONVAL??? Answer - 59%copper, 0.3% brass, 2.5% lead, 0.3% nickel, 0.05% aluminium, 0.4% ferus, 0.2% imperities trace, reminder Zinc.
As we said before, it's a type of brass - and it's been available for years. Some boat builders have used it under water - others won't. At least you now know what it is and can decide for yourselves.
We hope this helps - and with your permission will provide a link on the next post to the full data table once sorted.
It’s always good to see a supplier put his head above the parapet. Even if they are spraying buckshot as their first salvo [img]/forums/images/icons/wink.gif[/img]
I look forward to future inputs.
<hr width=100% size=1>
__________________ Beating is sailing for 2x the distance at 1/2 the speed & 3x the discomfort
You say ...down to ... ...incorrectly placed/lack of Anodes. Make sure the anode is in sight of the through hull fitting. Make sure they are all bonded.. That statement demonstrates that these components are not suitable for underwater use, because if they need protection it means that they are susceptable to dezincification.
An underwater fitting should be corrosion resistant such that cathodic protection of it is not necessary. Such a fitting should be able to be installed on frp or timber boats, especially, with no need for any bonding or cathodic protection whatsoever. In fact, in the accident report referred to in the previous thread that initiated the questions regarding the suitability of Tonval, it actually went further than that and stated that the bonding may have contributed to the failure of the fitting.
John
<hr width=100% size=1>I am the cat but I am only 6.
Agreed John. It will be interesting to see how this retailer responds to detail rather than simply protest that I maligned them, which of course was never my intention anyway.....
I have to say as a retailer, ASAP do a good job, but moving into the area of giving technical advice is in my opinion not a retailers job and they are digging a dangerous pit for themselves by trying to do so without seeking expert advice.
The thought that every skin fitting should have an adjacent anode is not only impractical but entirely the wrong solution. There is no need to fit anodes or bond fittings to them if they are made out of gunmetal as there is no zinc in gunmetal to be depleted in the first place. The argument that you save money by fitting cheap alpha brass fittings and then spend a small fortune plastering the boat with anodes to protect them is not only silly from a technical viewpoint. It would cost more than fitting gunmetal in the first place!
What the hell is TONVAL???
Hybrid Mode
