Author Topic: Spot welding.  (Read 15468 times)

AndyL

  • Quite Chatty
  • ****
  • Posts: 402
Re: Spot welding.
« Reply #15 on: December 27, 2014, 11:11:20 AM »
I order from overseas all the time, no problem.

If you want an adhesive, by far the strongest are the modified acrylics. These are stronger than epoxy glues, totally waterproof and far less sensitive to contamination and have a very long shelf life (I'm still using glue about seven years old). It's also less sensitive to mixing ratios.

There are various types you can get, but I would recommend getting it from Starloc, as they're the cheapest, but the products are first class.

If you prefer a branded name then Devcon Plastic welder is a good product (don't be fooled by the name, it's not just for plastic). You can usually pick that up on ebay.

http://www.shop4glue.com/acrylic-sga-methacrylate-toughened-adhesives-66-c.asp

http://www.devcon.com/products/products.cfm?family=Plastic%20Welder%E2%84%A2
1959 LHD 3-wheel Isetta.

messyman

  • messerschmitt kr200, frisky, isetta 300
  • Quite Chatty
  • ****
  • Posts: 162
  • messyman motors
Re: Spot welding.
« Reply #16 on: December 27, 2014, 11:41:29 AM »
id use pu adhesive made by stachem (who makes tack cloths ) very strong its used as a seam sealer and a panel adhesive

soft solder (lead fill) uses low heat and it bonds (tinning)

mig uses pre drilled holes and if its done very slow it wont worp

gas welding is also an option

brazing is apparently the strongest weld but u have to use heat (high heat)

spot welding is fusing metal in a spot form for bout 4 seconds

tig weld poss option but still using heat

theres just a few confusing types of welding
messyman restorator of rust relics vw or bubblecars
www.vw-specials.forumotion.com
Messerschmitt kr200 x2 ,frisky family 3 mk1 shell,isetta 300 lhd chassis, vw polo,vw caddy mk1 , t4 , mini , my dad has 2x Messerschmitt kr175

Bob Purton

  • Prolific Poster
  • *****
  • Posts: 5041
    • Inter microcar
Re: Spot welding.
« Reply #17 on: December 27, 2014, 01:00:02 PM »
Thanks Messy. How do you suck those eggs again? ;D

Bob Purton

  • Prolific Poster
  • *****
  • Posts: 5041
    • Inter microcar
Re: Spot welding.
« Reply #18 on: December 27, 2014, 01:31:54 PM »
I thought one reason for using spot welds was it deformed the sheet metal less.

Having watched Mick do it he used some rivets to get the fit correct, or the threaded thumb clamps, forget what they are called, if they will go in. With the thing located he would then weld in a way rather like tightening a cylinder head. This spread the loading along the seam. Once the spots were holding the job the rivets/clamps came off and the job was finished off, lastly filling in the original clamp/rivet holes.

Of course proper spot welders are a clamp as well. that is a problem when you cannot access one side of the weld, or the electrode energy is dispersed by being away from close proximity to the the other, on miss matched metal thickness. it can turn into a zipper, a known prob on Schmitt monocoques.

Interestingly the normal screen surround I have found on low production cars is a channel with rivets, not least as the channel is sometimes brass extrusion. It is more malleable and chrome's up nicely. Even tin bodywork is riveted onto brackets hidden under the surface. I actually have a box of Misc rivets for repairing such things. Though cheaper cars can have a panel with a hole cut in and the screen rubber mounted. This rarely looks well.
True Al but you still need specialist tooling to form a tight bend in brass channel. Ever tried it without?
With this project I had very little option after searching for a suitable screen for the last seven years, and no joy. I finally found a screen from a boat that has the right curvature but slightly smaller all round. Only option was the sheet steel and screen rubber route. Looking ok though!
When you say mick, are we talking about Cooperman?

messyman

  • messerschmitt kr200, frisky, isetta 300
  • Quite Chatty
  • ****
  • Posts: 162
  • messyman motors
Re: Spot welding.
« Reply #19 on: December 27, 2014, 03:03:56 PM »
cadburys crème egg a bit of a bugger the goo inside a bit thick ,as with a normal egg well raw dosent come into my diet  :P
messyman restorator of rust relics vw or bubblecars
www.vw-specials.forumotion.com
Messerschmitt kr200 x2 ,frisky family 3 mk1 shell,isetta 300 lhd chassis, vw polo,vw caddy mk1 , t4 , mini , my dad has 2x Messerschmitt kr175

Bob Purton

  • Prolific Poster
  • *****
  • Posts: 5041
    • Inter microcar
Re: Spot welding.
« Reply #20 on: December 27, 2014, 04:27:03 PM »
 ;D

Big Al

  • Prolific Poster
  • *****
  • Posts: 4578
  • Ranttweiler, biting the breeze block of banter
Re: Spot welding.
« Reply #21 on: December 27, 2014, 05:05:55 PM »
I would bow to folk who have actually constructed such things, rather than repaired them. Certainly sections are not easy to bend and to keep an unbent, unified look, as though no stress has been introduced. So a screen was found, good stuff.

No, it was Mick Leeson using his aircraft fitters skills. Mike Cooper is a great free hand welder. He used to weld 2CVs by sight. I think he limits welding a bit these days after years of looking at, and breathing it.
Messerschmitt set, Goggo Darts, Heinkel 175, Fiat Jolly, Autobianchi, Fairthorpe Electron Minor, Borgward, Isuzu Trooper
Citroen BX 17TZD & GTI 16v
Held - MG Magnette ZB & 4/44
For sale - Vellam Isetta, Bamby, AC Type 70, Velorex, Church Pod, Reliant Mk5, KR200,  Saab 96, Bellemy Trials, Citroen BXs

plas man

  • Quite Chatty
  • ****
  • Posts: 280
Re: Spot welding.
« Reply #22 on: December 29, 2014, 04:11:39 PM »
interesting reading so far . I think I'd be tempted to braze/bronze weld the said bits - that is if there is sufficient good stuff to braze to . you could use carbon's on low amp's  ???  (morgan or eagle 6mm rods preferred) .

Bob Purton

  • Prolific Poster
  • *****
  • Posts: 5041
    • Inter microcar
Re: Spot welding.
« Reply #23 on: December 29, 2014, 05:08:19 PM »
Well, I picked up a new co2 bottle today for the mig and decided to experiment with some scraps of metal.
First, plug welds, done a lot of these before on both the schmitt and the first Inter but always made 10mm holes in the top sheet. I just dont have the area to use 10mm on this job so tried as someone on here suggested, 5mm holes. The welds looked great but there was no penetration and they pulled apart with no effort. Then tried again with 10mm holed and they were as strong as you like. I guess the 5mm holes just dont allow enough heat through to the surface beneath.  Shame I cant use 10mm plugs on this job but there we are.

Next thought of trying stitch welds with the mig along the top inner edge. This worked great and didnt perforate the 1mm sheet or distort anything so I think I will go with this method, a neat row of about 8mm long stitch welds then I can bead some panel sealant over the top to tidy it up.
At least I now have a plan. Lets see how it works out on the actual job.
 Thanks for all the suggestions and input.

AndyL

  • Quite Chatty
  • ****
  • Posts: 402
Re: Spot welding.
« Reply #24 on: December 29, 2014, 06:22:05 PM »
I could never get on with using Co2 as a shield gas (not technically an inert gas is it, so it's actually MAG welding)

I found Argoshield gives far superior results, which is a blend of Argon, Co2 and Oxygen. I found the arc more stable very low spatter, and much better weld penetration especially when welding thinner gauge materials.
1959 LHD 3-wheel Isetta.

Bob Purton

  • Prolific Poster
  • *****
  • Posts: 5041
    • Inter microcar
Re: Spot welding.
« Reply #25 on: December 29, 2014, 07:29:42 PM »
Over the years as I have done jobs for others with the mig and in payment they have bought me bootles of gas of all makes and combinations and to be honest, I have barely noticed any difference.
 Its only a SIP welder a diy jobby really so I dont expect pro results all the time. I cant get on with those gasless wires though, tried one once and is was pants! I'm actually much better with my stick welder but obviously on heavier gauge steel. Thats a SIP as well.

AndyL

  • Quite Chatty
  • ****
  • Posts: 402
Re: Spot welding.
« Reply #26 on: December 29, 2014, 07:43:59 PM »
I use a SIP too- Autoplus 130.

When I first used it I tried Co2, because it was cheap, and I was advised that it would be fine for the work I wanted to do. It was Mike Hurn that first switched me on to Argoshield.

I'm surprised you say you notice no difference, I personally found it made a dramatic difference to the quality of the weld.

The other big innovation for me was the introduction of self darkening visors.
1959 LHD 3-wheel Isetta.

Bob Purton

  • Prolific Poster
  • *****
  • Posts: 5041
    • Inter microcar
Re: Spot welding.
« Reply #27 on: February 11, 2015, 05:24:21 PM »
I finally found some time to finish the windscreen frame I started over the holidays. Here it is in primer. The welding method I decided upon, that of stitch welds covered by a bead of filler worked out ok.

richard

  • Rich
  • Prolific Poster
  • *****
  • Posts: 4458
  • Bond ,Gordon,Bruetsch
Re: Spot welding.
« Reply #28 on: February 11, 2015, 05:43:30 PM »
often wondered if you picked up the Dunkley from Jean , you never said  ;) screen surround looks excellent
outside of a dog a book is mans best friend. Inside of a dog it's too dark to read .Groucho Marx 1895-1977

blob

  • Prolific Poster
  • *****
  • Posts: 1276
Re: Spot welding.
« Reply #29 on: February 11, 2015, 05:44:56 PM »
Great stuff!