Glen-L.com

Can anyone answer why that it is not suitable to weld Glen - L boats with oxy - acetylene welding - with the suitable means being either mig or tig. I am using DHC 2000 which is the refined version of OFW producing strong welds (equivalent of tig strength etc), pliable and strong. The DHC 2000 previously Henrob which has a much narrower heat affected area similar to tig and mig and eliminated oxygen from the weld affected area unlike conventional oxy - acetylene welding gins like Metco.

I have used this method in a shop setting to do weld test on the coupons. I have found the welds are very succeptable to porosity in the welds. You will also find this problem when using MIG with aluminum if you use a "whipping" motion with the gun. With any aluminum welding process it is very important to protect the integrity of weld puddle to eliminate the problem with porosity. With the OFW system the circular motion favored by many will created the porosity issue.

In theory the process will work, but I am not sold on it. Are you wanting to use that to avoid having to purchase a MIG or TIG machine? I am not sure I see any advantage of using the OFW process. In fact I see more problems with the process when compared to the other processes.

cheers mcm builder - yes the intention is to not purchase a mig in favour of OFW - the technique of welding is the same as a tig with no swirling - I have done a lot of practice runs and perosity is not an issue - the DHC 2000 gun is by all the sellers promotional talk is that the weld puddle is totally protected eliminating excess oxygen from the weld puddle and the 2 gases are mixed inside the gun as apposed to at the flame region as is the case with normal OFW. The gun is pretty amazing I just are concerned that I build the Tiny Might which all looks good at the end but structurally comprimised by the welding process. The welds are sound in apearence and I have bent then, ground them to see any weld faults but I have not found any - welds are pliable though - the process is easier than mig and tig to learn.

tintin,
The test used to see if any weld process is correctly applied in aluminum plate is the brake-bend test.

Butt, fillet, single sided or double sided welds are all done in the same alloy and thicknesses as the boats' many joints. These would typically be 6 -12" long segments or coupons. When the welds are done and cooled without liquids, a section a few inches long of the weld coupon is cut and bent.

The various sections have different bend specs but generally the weld should bend fully over and fully back; that is, a Butt becomes a U one direction then a U the other direction and the weld should remain intact. In the case of the single sided fillet- the weld is 'back' bent flat to the T so the vertical leg is horizontal and then back up to vertical bending toward the side of the weld. The double sided fillet is done 180- two 90 degree bends of the vertical leg and the single sided is done 90 down to the flat and back up to vertical.

When bending the U's in the butt test a die is used to keep a 4T radius of the metal and when bending the fillet's test the vertical leg is not hammered flat to the horizontal leg so the 'natural' rounding is left in the parent metal legs. If you don't have a U section press frame, then just leave 3"-4" legs and hold the test piece in locking pliers or one end in the vise and the other with an adjustable wrench to keep the bend from 'kinking' or having an angle point at the weld.

50 series alloys will make more trips over and back than 60 series which is more brittle and less malleable an alloy series. These bends will showup excessive root porosity, brittleness of welds, weld end crater cracking failures, and other common weld failure modes in aluminum welding.

In all cases the weld should hold and the parent metal should fail before the weld does. I'd expect all test failures to happen at the edge of the HAZ near the toe of the weld leaving just a slight margin of parent metal outside the weld's outer most edge.

I have not used these torches so I can't offer any remarks about them, pictures are always helpful though. Have you tried and inside fillet with a 3/8" bar butted to a 3/16" plate? Electric systems have the excess 'heat' to initiate/create the fusion puddle in this weld and it would be interesting to see the results with a gas torch?

cheers,
Kevin Morin

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Kevin Morin

hello kevin this is the link for DHC 2000 test results http://www.amweld.com.au/results.htm by all accounts the process is completely different to OFW and more similar to Tig but is much faster travelling speed.

tintin,
I visited the link; but none of the results were break/bends -that I found- and none of the welds, reported, appeared to be on 5052, 5086, 5083 alloys? Just an ad site- it appeared- so the info is mainly sales related, not the kind of info I'd need to see to spend time with this system.

I'd look for a more third party type of site- where someone built some fuel tanks or did some hull seams with this torch and shows some positional welding results. Especially interesting would be an inside corner of the transom- up hill of down hill, where the gases would be essentially trapped in the work space.

I use a hand held, motorized, cold wirefeed TIG system so this method won't approach the rate of TIG deposition in our shop, but it may rival tip rod with two hands- I think that a decent TIG hand would do just as well as a gas welder?

How is the bead on 0.060" (1.5mm) sheet- or 0.040" (1mm)? That is a decent test of a tool's weld control claims and demonstrates the scalability of the weld bead- downward.

Also it would be interesting to see the outside corner puddle penetration- "sag" of the bead into the back side of the weld. I find that control of this penetration changes the entire bend break test results for thin TIG welds on tanks and various hull parts with only one plane of access.

cheers,

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Kevin Morin

tintin,
I do welder qualification test as an independent inspector. If you cannot find some place to test the plates for you I will be glad to do so at no charge just to see the results for myself. Do a simple open butt weld joint on the alloy you are wanting to use. Send at least one 6X6 coupon for each position you want tested. I will do a face and root bend for each position. I will also cut the welds if the material is >1/4" to see if there is any underbead porosity. Email me and I will send you my address.

I also checked the link and I also think it is more a promotional link than one for actual application. The process may be a very good process and I am not meaning to sound negative about it, but you need to be sure it does produce a structually sound weld.

Thanks Kevin and MCM - funny how I share similar thought patterns to yourself - yes the link is pretty promotiomal - you tube have videos which show you the welding process through the welding googles- I did buy a dvd from fourtier enterprises (USA) whereby the dhc 2000 is mainly used for custom motor bike work - all welds seen and done by myself are on one plane at this stage I like the idea of getting coupons tested - Im in Aus W.A where are you MCM Builder? - The gun is interesting as an alternative to tig and mig as I think you would agree - worth a good look and the welds tested to fully evaluate if it is as good as the promo hype - I will try the welds as you have mentioned and i will come back with the findings.

.

I apologize I thought my email address was listed on my profile.
The address is wejohns@yahoo.com Send me an email and will send you my address and what you need to do as far as the welds.