so after reading the rx7 thread and the heated arguments, i guess i'm wondering about good easy setups for backpurging that work well.

so i backpurge some of the time. when i do, i'm not getting very good coloring. its better then sugar and it does have a little color, but nothing like i've seen on here.

i guess i'm wondering how most of you guys do it and if there are some things you suggest to get good coloring?

my main problem would be somthing that can plug the end of a 90 and can withstand some heat.

also, when i'm welding runners, there are usually quite a few gaps from the pipe connections. should i cover those while i'm welding one and then keep uncovering them until i'm done?

hope this doesn't sound too retarded.

 

lol i think i kinda started that but didnt mean to
But I would imagine that you should start with the gap closest to the gas source and go from there.

 

we use aluminum tape at the plants, i have no idea how much it costs, but you can wrap the weld area with it and just weld it out and the aluminum tape melts away and peels back without harming the weld. usually cap the end with the purge diffuser with it as well as the other end..

 

I never do any pipe bends, so the fit-up is always very tight at the welds.
I'm always having to get creative with capping the ends though. 3-hole falnges, v-band flanges, no flange,etc, etc. I have a few little pieces made up of wood for the flanges with bolt holes, works great. If it's far enough away from the weld, I just use masking tape on the end. I've even tacked a piece os stainless sheet to cap the end. It doesn't have to be perfect.
Also, I always blast it with about 50cfh for a few seconds when some air can get out, then I use 15cfh inside the tubes once it's sealed up for welding.

 

thanks for the input.

anyone have pics of thier setups.

aluminum tape sounds pretty sweet. so you wrap the whole weld and it blows away as you go?

 

I usually just stuff the ends with aluminum foil. Opposite end of where the gas is being fed I stick a small bronze tube (1/16") in there so some gas can escape. Then Ill wrap the joints that arent welded with some aluminum foil and masking tape. Seems to work well for me. Also, I dont get welds that are super colorful as posted on here but they do have some nice color.

 

so i talked to my friend about the aluminum tape. he mentioned its called venture tape?

anyone know where to get this stuff and if its pricey or not?

 

here ya go.

http://www.arc-zone.com/index....0_139

 

Save your money.

Use tin foil in the end of whatever you are welding and fit a tubing in the other. You can run a dual gate setup off one tank and learn how far to leave it opened. Works great and costs under $100.

 

at work we just stuff the end with aluminum foil and use a standard regulator line with foil wraped around the end to seal it to the pipe. i set the flow to 20cfh dont worry about the gaps in the pipe unless they are more than 1/16" they dont seem to affect anything.

you can see the aluminum foil around the hose in this pic:

 

 

gas goes in the bottom and the whole table rotates.


whenever backpurging make sure u stick some steel wool or a scrubby in where the gas enters, or else u dont get an even purge. (just like a gas lense)

 

Arc zone has it the cheapest. Believe me I looked around. At Home Depot or Lowes you can get expandable pipe plugs. Many sizes to choose from. Works great for pipe welding and is cheap.

Hope this helps.

James

 

I use aluminum foil, the rubber anti skid pieces you buy to slip over chair legs and a beer can works great for 2-1/2" tubing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SMSP &raquo;</TD></TR><TR><TD CLASS="quote">... beer can works great for 2-1/2" tubing.</TD></TR></TABLE>

awsome

yet another excuse to drink on the job. i've tried the aluminum foil tricks and honestly, its a pain in the ***. i havn't gotten it to work as well as i would like.

the pipe plug idea is pretty cool too. i tried to make one out of steel that had tangs that went on the outside of the pipe. it works on bend ends, however it doesn't seal that great.

 

I normally use foil. i take a piece lay it over the end of the pipe and hose clamp it on. every once in a while ill ball it up and stuff it in.

 

I use blue painters tape.

I have different steps of root purging so the runners dont warp when I weld them after breaking them off of the jig.

I have a seperate bottle of argon with a regulator and gas line, on the end of that I just have an air compressor chuck with a fitting in that. All I do is turn the purge on and snake the hose down the runner im doing, since there is a tiny gap you can see where the hose itself is.

I leave open any other small gaps on other spots to be welded so some of the gasses can get out, this way the oxygen can escape and the argon can pool.

The painters tape does a great job, leaves no residue, takes alot of heat before starting to char (it doesnt just burn up into a ball of flames) and can be re used once you take it off and when your done just chuck it. Its also good because its noticable (bright blue) and if one of my guys go to weld or use the vice they know that its either being used or hot and not to grab it. I also like it because I cant always do what I want in the shop especially if the dyno is running so I can write on the tape with a sharpee to remind me of where im at to pick up later.