Bodywork

[RickL]

temp crayons

Tonka,

I saw the temp crayons mentioned on another site for welding in patch panels on cars and was just wondering.

I use the back of my hand for temp testing surfaces.

Rick

[JimmieD]

RE: protection of safety glasses...

I have heard good reports about the products this company sells, like their lens cleaner/polish for plastic and polycarbonate materials.

http://209.204.217.51/products.htm

I have not used these products.

Another source is:

http://www.1-800-optisource.com/

They are in the eyeglass and lens business but I don't know if that makes their products any better than the other guys!? Haven't tried them personally either.

JimmieD

[RickL]

cut out the old patch

TonkaDoc,

Cut out the old patch, attched a couple of images for your review.

Since the cut is close to the reinforcment for the hood hinge wondering what to do there.

Thanks,
Rick

[RickL]

more pics

more pics

[RickL]

more pics

some warping due to heat

[Alex]

Rick

Just how big is the area you are patching? I am having a hard time telling from the pics.

I am about to start cutting the rusted areas from the dripline on my ambulance. I am kind of skittish about it after seeing the problems you have encountered.

Alex

[RickL]

patch size

Roughly the width of the glove box.

Rick

[tonkadoctor]

Hinge Area

Rick,
The hinge reinforcment is a blessing that will absorb some of the heat but a curse in that the metal in that area is probably the thinnest due to trapped moisture over the years (Mine are rusted through).

Looking at how thin the sheet metal skin is near the hinge I would go past it and drill new holes in the patch to line up with the hinge reinforcment.

Be careful near that pitted area next to the hinge as that is probably pretty thin too.

Also take advantage of the "hole" that you have right now to hammer that corner back into shape and it should be fine.

Looks good so far, You Can do this.


Alex, Take your time and have patience while woking over your drip rail area .

Remember that when the metal is as thin as a knife egde due to rust pitting it is nearly impossible to weld without blowing holes in it and you need to cut out bad metal until you get to good metal that you can weld

[JimmieD]

Say TonkaDoctor,

What about using the copper heatsink backer on those extra thin areas?

JimmieD

[tonkadoctor]

Copper Heatsink

Good Idea Jimmy, I forgot about that trick. A copper, aluminum or brass heatsink would work well when butt welding thin sheetmetal. but I think one area is too far gone for that.

Using a non ferrous metal backing like that is also a good way to build up a hole where you accidently blow through the metal.

The area I'm most concerned with is well shown in Ricks second pic where the metal looks razor thin. You have to be really good with TIG and use the smallest electrode possible to weld to that thin of metal. That's why I suggested he cut back a little farther, but I'm also concerned with the area next to the hinge where you can see alot of rust pitting. That area is also going to prove to be very thin

I don't have that kind of skill anymore (I used to be able to TIG weld 2 pieces of aluminum foil together just to show off in one of my shops, there was only one other guy that could do it)

[JimmieD]

Of course nothing says a patch has to be square or rectangular, but just a match for the hole. In this case I would consider an irregular patch shape, as cutting back into hinge section until things solid up wherever, and tracing whatever patch shape is necessary to accomodate the hole. Kind of like life: keep going 'til you get to the good stuff.

It would still be possible to force a 1/4 or 1/8 inch piece of copper beneath as a heat sink, and to allow a place to flow the puddle while welding in case of burn-through. As I understand it the heat differential of copper and steel, and rapid movement of heat through copper as it is sinked away, prevents weld from adhering except at weldment?

I'm not speaking from hands-on experience but more in the theoretical for you guys to scratch and hmmm... about!
JimmieD

[RickL]

game plan

Ok, so I am going to cut further into the hinge sheet metal to get to good metal. I was concerned about this area also.

I have a dolly but no body hammers. Would it be ok to tap(learned my lesson not to hammer) the warped area with a flat face of a ball peen hammer?

What should the next step be install flanges? The area at the front of the cowl could be a bit tricky.

What would the effect of too low a flow of argon\co2 be on a mig weld? Wondering as I was running it at 15 cu ft and according to the Lincoln site it should be at 24-26. I already noticed a different weld profile when welding another job.

Rick

[tonkadoctor]

Cowl repair

The non ferrous metal backings will be easy to remove when done welding as the weld should not adhear to the copper. It might stick a little.

Using too low of a flow of gas causes porosity due to contamination of the weld and makes it difficult to weld, however, too much gas causes the same problem as it it litterally blowing away due to turbulance caused by the pressure. Use some scap to try different settings until you are comfortable with what works best for you.

for the front edge of the cowl I would just bend the patch 90 degress and tuck it inside the cowl, don't worry about putting a flange in this area.

For hammering out the warped area, I would work out the corner and not touch the center of that cut as that corner is where the pressure points that are holding the sheetmetal in it's warped state are located. don't try to get it in peftect shape as that would stetch the metal just get a basic rough shape that can be easily filled later and when you tack weld this side quench it to help shkink it as you go.

[RickL]

ready for next lesson, sensi

worked on the wrinkle and cutting back more material. These are the tools used for fixing the wrinkle.

[RickL]

completed fix

This is the completed fix on the wrinkle.

I next took a paper bag and used it to rub the outline of the hole to make up the patch.

I will post the picture of the patch next.

Rick