Haynes Forums - welding

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hi just a quick question, im new to welding and will be practicing while building the car,

how do you tack weld the chassis togeter without catching the wooden table on fire?
i plan to use the same wood as the book states plywood i think? and im worries about the fire hazard :/ can anyone help with any tips etc

i would love to get a pro welder in but on a tight budget so have to learn to do it myself

Just have a fire extinguisher handy. I've painted my board with white housepaint, and even with the welding spatter thast happens, the only fire i've had is when i accidently left some masking tape on the table under where i was welding. I wondered why the tasck weld i just did was smoking so much. :o :)

A bit of burnt on the build table wont be that bad. Looks like you have been busy at the end of the day.

thanks mate nd when doing the tack welds on the bottom chassis rails do you do the tacks on the top or side cause i keep thinking that if i tack on the top the weld will block the upright?

If you cut a 50mm hole under where you want to weld then the table can't catch on fire.

It would take a lot for your table to catch fire from a few sparks.Personally i found the spatter from fluxed wire worse than using solid wire with gas.Just make sure that when you pack up and walk away for the day nothing is smouldering.:D

Quote:

when doing the tack welds on the bottom chassis rails do you do the tacks on the top or side

Grind a 45' angle in each piece where they join then tack it.When fully tacked and your happy fully weld the top and then grind it back flush.

First, welcome among us !

Quote:

Originally Posted by kitcarkid (Post 62137)

thanks mate nd when doing the tack welds on the bottom chassis rails do you do the tacks on the top or side cause i keep thinking that if i tack on the top the weld will block the upright?

Yes you are right. Prefer tacking on the corners when possible, rather than on top. On places you will have another tube coming over the junction, you can tack on the side. There are some old posts about that on the forum.
Regarding fire hazard, just be very careful, and to back up "Aussie_Haynes_MX5", always have fire extinguisher ready in the workshop. A bucket with water and wet towels can also be useful in case of emergency.
The melting metal will mark the table, sometimes makes small flames, but as far as I'm concern, nothing more. (but I'm sure there are a lot of bad stories and experience regarding this matter:( ) For example, I have a paper map on top of my table as a layout, and of course, heat consumes the paper where you tack or weld, but it never got on fire.
Another advise to avoid fire hazard : when you finish welding for the day, find something else to do in the workshop for 15-30 minutes before leaving the place, so when you leave the room, you'll be sure nothing is burning, or you would have noticed it. For example, putting things in order, sorting out your tools and cleaning the table can give you this useful time. And you'll be glad to find your workshop in order the next day :)
Good luck for the building !

Quote:

Originally Posted by voucht (Post 62143)

First, welcome among us !

Yes you are right. Prefer tacking on the corners when possible, rather than on top. On places you will have another tube coming over the junction, you can tack on the side. There are some old posts about that on the forum.
Regarding fire hazard, just be very careful, and to back up "Aussie_Haynes_MX5", always have fire extinguisher ready in the workshop. A bucket with water and wet towels can also be useful in case of emergency.
The melting metal will mark the table, sometimes makes small flames, but as far as I'm concern, nothing more. (but I'm sure there are a lot of bad stories and experience regarding this matter:( ) For example, I have a paper map on top of my table as a layout, and of course, heat consumes the paper where you tack or weld, but it never got on fire.
Another advise to avoid fire hazard : when you finish welding for the day, find something else to do in the workshop for 15-30 minutes before leaving the place, so when you leave the room, you'll be sure nothing is burning, or you would have noticed it. For example, putting things in order, sorting out your tools and cleaning the table can give you this useful time. And you'll be glad to find your workshop in order the next day :)
Good luck for the building !

thanks mate thats a big help :)

Use standard building ply for your table its all got to be flame retardant treated now for building regs, BS EN 13501-1 and various other things. So it will scorch but not burn. Just watch everything else that you have lying round with the weld splatter. Clean work station and a fire extinguisher.

Andrew