Guest Mike Posted November 18, 2006 Share Posted November 18, 2006 I found a carb hat that I want to modify to fit my SBC. It has the vintage look I want. This will require cutting a 3+ inch section and welding the two outer pieces together. This on also has some ugly pitting (corosion??). For reference... this thing is about 18-20 inches long. QUESTION: Can the welding be done for a reasonable fee? Can the pitting be welded over so I can grind it down and polish the whole thing? I can cut the section out if that helps with price. Here are some pics... http://forums.hybridz.org/attachment.php?attachmentid=1715&stc=1&d=1163880854 http://forums.hybridz.org/attachment.php?attachmentid=1716&stc=1&d=1163880862 http://forums.hybridz.org/attachment.php?attachmentid=1717&stc=1&d=1163880869 http://forums.hybridz.org/attachment.php?attachmentid=1718&stc=1&d=1163880874 Quote Link to comment Share on other sites More sharing options...
PhZ Posted November 18, 2006 Share Posted November 18, 2006 Find a local shop, get a quote, make sure you exaplin completely what you want done, and they should be able to help you for around $50 it doesn't look that bad. I don't like welding Aluminum, not enough practice. It has to be really clean, it wouldn't hurt to have the parts ready to weld, prepped, or you'll pay them to do it and they might not be as careful. Hope that helps, don't be afraid to go to the local shop and talk to the owner in person, and it wouldn't hurt if you say you own a shop or something so they think there's more where this came from, they might even give you a discount. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 19, 2006 Share Posted November 19, 2006 PhZ... Of course this helps. All information helps. THANK YOU!!! Now I know that it's safe to buy the part. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted November 19, 2006 Share Posted November 19, 2006 hey mike, is it cast or not?, if it is cast (pot aluminum or us welders call it trash aluminum) it will make it harder for your local welder to do and cost more. and that is only if they can even do it. but remember this.... if you really want that done, make sure the welder has some of his work to show of the same material. i have known many welders that say they can do it and screw it up and claim that it wasnt their fault, but the metal was no good. so beware!! Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 19, 2006 Share Posted November 19, 2006 roninjiro... I strongly suspect that this part is cast. At least it "appears" to be judging by the texture. If it's really that much of a risk, it's not worth it. I'll just keep looking for something that has that vintage look I want. Quote Link to comment Share on other sites More sharing options...
lesd Posted November 19, 2006 Share Posted November 19, 2006 Mike, I've welded cast AL parts before, it is rather tricky. The 'pot metal' , or low grade AL that carbs are typically made from tends to turn to liquid much faster than good AL. The trick to welding it is to use bursts of a lot of power, to localize the heat. A square wave TIG would be a must. -Les Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 19, 2006 Share Posted November 19, 2006 lesd... Thanks for the tips. I won't be welding this myself... no experience and no welder. I'll keep this info in mind while looking for someone to do this work. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 19, 2006 Share Posted November 19, 2006 Welding cast aluminum automobile parts, especially old parts, is tricky. The two most important things are: 1. Identifying the cast alloy - look for a 3 digit number somewhere on the part. It might have an "A" prefix and would look like A319, A390, etc. Without identifying the casting, filler metal selection is hit or miss. If in doubt, use 5356 filler. 2. Cleaning - old automotive aluminum parts are dirty and they are dirty deep down. Running a wire brush over the surface isn't going to get the oils and oxides out. Hot tanking and/or pickeling the part is the best way to get it really clean. Then use a new stainless crimped cup brush on a hand grinder to really clean the areas to be welded. Set the balance on the welder 40% on (balanced toward cleaning) and expect to pull a lot of oxides off the material. Add in a lot of filler to try and dillute the oxide inclusions that are going to happen. Quote Link to comment Share on other sites More sharing options...
PhZ Posted November 19, 2006 Share Posted November 19, 2006 I'm not entirely sure what temperature ranges are acceptable for aluminum filled epoxy, but I have used it before and you can find stuff that is reasonably strong. We used it to fill oversized holes to redrill and retap and it didn't have any pullout on non-critical joints. I would suspect the strength is poor vs. structural grade aluminum, but vs. cast it couldn't be that bad. Also there are brands that have good fatigue properties. Anyway, call the shops and ask their opinion on cast parts, another good idea is to give them a sample of similar material and ask them to try it, they would most likely try it without charge. You don't want them to "try it" on the real part if you suspect it may be unweldable (as some have suggested). Also do some research on weldability of cast aluminum and with this information, ask the weld shops a few key questions, if they sound like they know what they are talking about it's a good chance they do. I'm not experianced enough with welding aluminum to comment on the weldability of cast aluminum, perhapse it could be analogous to the difficulties associated with welding cast iron? Most shops will be more than happy to talk to you in person, espeically if you say you are starting up a shop or something and are really looking for a welder to set up long term relations with. Then when they call back later after this project is complete, say "I went another direction with the aluminum, we are having them machined." or whatever. I think the key is to start a dialog with local shops. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 19, 2006 Share Posted November 19, 2006 Thanks guys. Maybe the best option for this part isn't welding. Perhaps some sort of glue and a decorative seem is the better solution. That said, I'd worry that the seem would look cheesy. I'll think about seem styles before bidding on the part. Bottom line is you guys stopped me from making an error and wasting my $$$. Thanks again:grin: Quote Link to comment Share on other sites More sharing options...
Careless Posted November 23, 2006 Share Posted November 23, 2006 Thanks guys. Maybe the best option for this part isn't welding. Perhaps some sort of glue and a decorative seem is the better solution. That said, I'd worry that the seem would look cheesy. I'll think about seem styles before bidding on the part. Bottom line is you guys stopped me from making an error and wasting my $$$. Thanks again:grin: you can probably have one custom made out of quality aluminum from a local fabricator instead of trying to get that one repaired. LOL. and it will be a one off! Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 23, 2006 Share Posted November 23, 2006 That's a possibility... though costly, I'm sure;) I wonder if there are any hobbyist metal-working shops around... with a CNC machine maybe?? Quote Link to comment Share on other sites More sharing options...
PhZ Posted November 23, 2006 Share Posted November 23, 2006 I used a formula when estimating a fabrication project once, something like if they charged $70/hr then they'll charge 1/4hr per setup plus machine time. A typical complicated part was $450 which turned out to be a good estimate on average. Of course a simple aluminum plate with a few holes in it could cost as little as $70, and they'll charge 2-3X more for steel machining costs. Usually material cost is negligible. In one case I got a couple turned parts, and a pair of really complex parts for $500 total, but I had made a deal with the guy to limit my maximum liability. I told him I'd give him $500 material included regardless of how much time he spent. Don't get nit picky about scratches, if it's aluminum you can polish them out easily. Ask for 6061 they'll have it laying around. (6061-T6 is a typical aerospace material for machinign pruposes, it's tough and strong.) You could get lucky on price, but I recommend negotiation before they agree on the job, and get the following in writing: 1. Agree on a total price 2. Agree on a due date and give them some monetary incentive for early delivery, and tell them you need it by some special event and you have a backup part so if it's not done by the deadline you don't want it (be reasonable, make up the event date after he tells you approximate timing). 3. Schmoose, compliment, get a good dialog going, don't go in a rush, and don't get nervous. Talk about a bad experiance you had with one of his competitors etc. 4. Write everything up ahead of time on a contract, fill in the dates and sign it with him. This works wonders for getting a lower quote and if he's excitied about future work you may give him, he might even get it done same day. Sorry for the long post. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted November 23, 2006 Share Posted November 23, 2006 PhZ... Thanks for the advice. If I opt to have a part made, I'll take all this to heart. Quote Link to comment Share on other sites More sharing options...
Sparky Posted November 23, 2006 Share Posted November 23, 2006 Excellent advice in this thread! Quote Link to comment Share on other sites More sharing options...
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