BlackBeaut Posted July 6, 2005 Author Share Posted July 6, 2005 Did you try sticking the bush's in the freezer overnight before machining? Have heard that makes a difference. Hmmm' date=' that sounds like a pretty cunning idea, I'll pop one of the buggered bushes in the freezer today and see how it comes out. I was told a while back by a machinist that the best way he'd found to work poly was to grind it. When you weld that frame up, that top member will warp downwards on the outer ends a little, pretty hard to avoid no matter what you do really, it would pay to tack weld the whole thing together first before fully welding. That way the outer ends will be braced by the diagonal member that you will have in there. Good plan that man! Cheers, Rob Quote Link to comment Share on other sites More sharing options...
peej410 Posted July 7, 2005 Share Posted July 7, 2005 if you have trouble machining the poly, look into delrin, it machines beautifully and even though its much more stiff than poly its a good choice for such things Quote Link to comment Share on other sites More sharing options...
BlackBeaut Posted July 11, 2005 Author Share Posted July 11, 2005 Behold and fear my skill!! rats OK, in my defence I've never used a welder of any variety before. This is MIG with flux-cored wire as I haven't got anywhere I can inside. I couldn't be bothered to keep spraying on the anti-spatter spray for these tests, it does seem to help a lot though. I do think though that it would take a FBH to dismantle these works of art. I'm thinking maybe I should pop them on ebay, there's bound to be a complete nonce out there who can see exactly what my tortured soul was trying to put across with the conceptual mixing of the metaphorical nature of all that is transient I'm particularly pleased with the inclusion of spindle pin ends, adds a very Datsun feel to the piece Back in reality I'm not 100% convinced if I should weld up the rear frame, it didn't seem to make a huge difference which setting I had the welder on (it's a 150A turbo jobby) OK the bead was wider with the higher setting which is probably a good thing. I couldn't run the wire speed any higher than minimum without it getting stuck or something. None of the beads had that nice ridged look that the pros seem to be able to knock out in their sleep. Hmmmmmm. Still a bit of action with an angle grinder and a quick visit to the sandblaster would probably make all the difference. As for progress, I've got all the parts ready now. Sorted out the delrin bushes - absolute breeze to machine. Got the cut outs done on the two main uprights for the bush shells, and I've drilled the 4 mounting holes along the top piece. So it really is just time to get the damn thing welded up. Cheers, Rob Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 11, 2005 Share Posted July 11, 2005 My friend welded the leaf spring perches for his Toyota 4x4 with a flux core welder. The welds were ugly, but he took me through the Rubicon trail with that truck just fine. It just seems a shame in your case to have such nice machining be stuck together with such ugly welding. I'd suggest you see how much a professional would charge to weld it all up for you. You could even tack it all together then have a pro finish it. Quote Link to comment Share on other sites More sharing options...
tube80z Posted July 11, 2005 Share Posted July 11, 2005 Back in reality I'm not 100% convinced if I should weld up the rear frame' date=' it didn't seem to make a huge difference which setting I had the welder on (it's a 150A turbo jobby) OK the bead was wider with the higher setting which is probably a good thing. I couldn't run the wire speed any higher than minimum without it getting stuck or something. None of the beads had that nice ridged look that the pros seem to be able to knock out in their sleep. Hmmmmmm. Still a bit of action with an angle grinder and a quick visit to the sandblaster would probably make all the difference.[/quote'] Ah, the joys of MIG welding. One problem with learning to MIG is that a cold weld can look good. I'd recommend cutting the parts apart to check for penetration. A lot of MIG can be learned by sound. When it sounds like bacon sizzling you're generally setup correctly. Remember that MIG starts cold so you need to work this into the weld or you'll have a weak spot when you start out. Or you can heat it up with a torch first and have a lot less problems. For all your cool work I'd take it to someone and have it TIG welded. Then you can sell it for art if you don't like how it turned out Cary Quote Link to comment Share on other sites More sharing options...
BlackBeaut Posted July 11, 2005 Author Share Posted July 11, 2005 I'm hearing you guys. Will get on the phone tomorrow and see what I can find out. Might also check out the local college for some welding courses, would be good to maybe get a lot better with this craziness - I've got a rusty Z after all Cheers, Rob Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted July 12, 2005 Share Posted July 12, 2005 Hi Rob, If i were you i would not learn to weld on this part of the car, your rear frame actually does quite alot, needs to be strong, and as someone else mentioned, you may get a mig weld "looking" good but it may only be sitting on the top of the material and have no penatration at all, and it can just fall off! You have gone to alot of trouble so far with all that trick design work, the machining of the half round bush blocks etc etc, dont ruin it all now with some crappy welding mate. Get it welded by a professional. Spend some time learning/practicing to weld on a bunch of other rubbish parts etc, so that you can do it all yourself eventually. But dont comprimise your nice rear cradel. Clint T Quote Link to comment Share on other sites More sharing options...
clint78z Posted July 12, 2005 Share Posted July 12, 2005 Part of my job is testing welders, coupon are are bent and stretched to failure. Mig will fail before proper stick weld every time. The mig just doesn't put in enough heat and fusion is not as solid. Grinding, fitup, and getting a proper root weld in there are keys to a good weld. In anything structural STICK WELD is the only thing allowed. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 12, 2005 Share Posted July 12, 2005 Mig will fail before proper stick weld every time. The mig just doesn't put in enough heat and fusion is not as solid. Grinding, fitup, and getting a proper root weld in there are keys to a good weld. In anything structural STICK WELD is the only thing allowed. Well, yes and no. If proper preparation is made for GMAW welding then it will be just as strong as any other welding method. But, proper preparation for GMAW welding is not the same as proper preparation for SMAW. GMAW on steel sections thicker then 3/8" require a double V groove and U grooves are required on sections thicker then 1". Also, the type of spray transfer also affects penetration. If the typical short circuit type transfer is used then penetration will be less then ideal in larger sections. If a globular, pulsed spray, or spray types of transfer is used deep penetration can be achieved and amp levels of 400 DCEP is possible. In the structutural and pipe fitting classes and testing I saw at Lincoln Electric, GMAW was perfectly acceptable and was tested for. Quote Link to comment Share on other sites More sharing options...
BlackBeaut Posted July 12, 2005 Author Share Posted July 12, 2005 In English please guys In relation to my needs here, all the tubing is 3mm thick mild steel. The only area of extra concern is where the vertical tubes meet the machined bush caps. Also there are some acute angles (where the diagonal sections meet the horizontal and verticals) would there be issues there with getting a MIG or TIG torch in close enough? Only had a chance to ring one guy today (closest to me so first on the list) unfortunately he's on an extended contract. Seems to be plenty more welders in the phone book though. Cheers, Rob Quote Link to comment Share on other sites More sharing options...
clint78z Posted July 12, 2005 Share Posted July 12, 2005 Well' date=' yes and no. If proper preparation is made for GMAW welding then it will be just as strong as any other welding method. But, proper preparation for GMAW welding is not the same as proper preparation for SMAW. GMAW on steel sections thicker then 3/8" require a double V groove and U grooves are required on sections thicker then 1". Also, the type of spray transfer also affects penetration. If the typical short circuit type transfer is used then penetration will be less then ideal in larger sections. If a globular, pulsed spray, or spray types of transfer is used deep penetration can be achieved and amp levels of 400 DCEP is possible. In the structutural and pipe fitting classes and testing I saw at Lincoln Electric, GMAW was perfectly acceptable and was tested for.[/quote'] Good clarification johnc, I seen you have done this once or twice before. It is true that Mig (GMAW gas metal arc weld) can be used in certain structural purposes. I do qualify people on these pressure vessel welding proceedures. Even the good welders with stick SMAW have problems when it come to Mig root welds getting proper penatration. Yes we used short circuit and it's tricky. In general I have found more nice looking mig welds that fail than stick. With stick if you do it wrong usually you burn through or it looks like crap. If this happens usually the person gouges it out and does it properly. For a proper weld mig or stick the material should fail before the actual weld zone. Destructive testing is a good way to see if your welds are up to snuff. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 12, 2005 Share Posted July 12, 2005 Isn't this kind of a pointless argument to be having here? We aren't building ships, we're welding .120 wall tube. Mig should be more than sufficient if its done properly. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted July 12, 2005 Share Posted July 12, 2005 Awww...come on Jon: Over-engineer and under-utilize!! Quote Link to comment Share on other sites More sharing options...
johnc Posted July 12, 2005 Share Posted July 12, 2005 Man, I thought all you Chebbie V8 guys started with 3/8" plate and worked up from there. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted July 12, 2005 Share Posted July 12, 2005 Yeah...we use man sized materials!! I think it is referred to as "compensation", but I never knew what they meant by that! Quote Link to comment Share on other sites More sharing options...
clint78z Posted July 12, 2005 Share Posted July 12, 2005 You are right most welds even by a novice should hold quite a heavy load. The only time I would be extra concerned about a sound weld is on a-arms or other things are a safety issue and are subjected to repeated loading. Practice makes perfect, don't rush the prep work. Quote Link to comment Share on other sites More sharing options...
tube80z Posted July 12, 2005 Share Posted July 12, 2005 Practice makes perfect' date=' don't rush the prep work.[/quote'] And read Prepare to Win. Cary Quote Link to comment Share on other sites More sharing options...
tube80z Posted July 12, 2005 Share Posted July 12, 2005 Man, I thought all you Chebbie V8 guys started with 3/8" plate and worked up from there. A local shop used to think 0.25 inch plate was the end all solution for everything. Somewhere I have a set of lower control arms with two quarter inch thick tabs for the sway bar mount. Never mind the arm is no where near that thick. They built a lot of dirt cars. Cary Quote Link to comment Share on other sites More sharing options...
BlackBeaut Posted August 21, 2005 Author Share Posted August 21, 2005 Well they say miracles happen, and today I found myself at a loose end so I got my butt in gear for a change and made some progress. After being given the run around by so called professional welders with their "no probs mate, we'll be able to do that next week sometime" etc., etc., the old adage "if you want a job doing, do it yourself" came into play. I ditched the flux cored wire and got some argon/CO2 mix with 0.8mm wire and had at it. I'd say 75% of the welds were good first time, so I got the added bonus of practice with my angle grinder as well Definitely no close ups on the welds What's the general concensus on cleaning up welds now? I was thinking of just sandblasting the whole thing and slapping the POR15 on, but should I be considering grinding the welds at all? Colour me innocent! Hopefully now that I'm getting the hang of the welding, the second part of the cradle won't be so long in the making. Especially as I have a very nice set of control arms from ArizonaZ just waiting to get mounted to something! Cheers, Rob Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted August 22, 2005 Share Posted August 22, 2005 Hey Rob, Nice one, looks like you are making some real progress with this now!! What are you going to do in regards to getting a bolt up through the inner end of the transverse bar? (above the round bush mount) I generally dont like to clean up welds with a grinder, (dont want to remove too much weld/metal) you could possibly use some kind of sanding flapper disc to clean up any splatter etc. I hope you had the heat wound up when you were welding the tube to the solid steel parts, as it would take alot more heat to get good penatration (now theres a word i like ) into the solid. You dont want them falling off! Nice one Rob. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.