My 1970 GMC “Project Splice”

[Kronald_70GMC]

Hello everyone. I spent an hour in the shop after work today and managed to get my floor pan close to fitting. Still gotta beat it around a bit more yet and do a little trimming. The second picture shows where I really had to unleash hell on it.

[Kronald_70GMC]

More progress to report. I was trying to figure out how I could bend the flange at the front edge of my floor pan. I thought about a brake but it was not flat enough to put in a brake. Then I found some vise grips that would work perfect! Rather than buy them, I figured I would be resourcful and re purpose a pair of old vise grips that my dad had lying around. Couple pieces of scrap metal and about 2 mins of welding and bam! So now that Ive got that out of the way, the slow process of trimming down to fit slowly so as not to cut too much off can continue. Starting to see some good progress here! :metal

[69Tom]

Nice work. Ton of metal repair you're having to do. You may not be happy with your welds, but I'm really impressed with your cuts. They seem super precise. What are you using?

[Kronald_70GMC]

Originally Posted by 69Tom

Nice work. Ton of metal repair you're having to do. You may not be happy with your welds, but I'm really impressed with your cuts. They seem super precise. What are you using?

Thanks for the compliments. As far as my welds go, Im noticing slow improvment so hopefuly by the time Im onto body panels, Ill be a master. And for my cuts, I am using a Makita 5" Angle grinder.

[Kronald_70GMC]

And we now have a floor pan! I finished up all the prep on my flange and got it fitting the way I wanted and welded her up. Still have a little grinding to do by the transmission tunnel then its on to the next piece.

[ryans69chevy]

Very cool stuff! I like the vise grips! I was going to do that but after looking at harbor freight the price was too good. The progress you are making is making me jealous! At this rate you will be done in no time!!

[Kronald_70GMC]

Originally Posted by ryans69chevy

Very cool stuff! I like the vise grips! I was going to do that but after looking at harbor freight the price was too good. The progress you are making is making me jealous! At this rate you will be done in no time!!

Thanks! The vise grips are awesome! I realize I could have got them for 20 bucks here in town but these cost me nothing. Now I have 20 bucks for other parts or supplies! I do hope I will be done in no time as well. Just need to get the truck home before that point.

[Kronald_70GMC]

Well Ive been busy the last couple weeks in the garage, unfortunately not working on my truck though. Not till today anyway. I did a good clean and decided that two toolboxes was pretty overkill, so I sold the smaller one and extended my bench. After a little bit of electrical work, I got myself setup with a mini fridge in the shop! I also got myself a new shop stereo. Bought a new one for the house so the old on is in the garage now. Complete with subwoofer and all. Now that thats all wrapped up, Im back on rust repair. Got the other portion of my inner rocker welded in today!

[Kronald_70GMC]

Back at it. The last couple evenings Ive been in the garage working on the truck. Ive got most of the floor pan welds ground down. Then I really took some time comparing the arch of the new floor pan to the passenger side and found out that the new floor pan has a 3/8" high dome to it. So I have been heat shrinking the dome down to where it needs to be so the cab support bracket will fit properly to it. Its proving to be alot of work but it is definatly worth it. Now I get to take all the wrinkles out of the aftermarket floor pan and it is starting to look more like factory now.

[Kronald_70GMC]

I finished up with my heat shrinking last night. Back to the grind now. Ive got a full day planned in the shop tomorrow so hopefully I can finish up with grinding my welds and possibly get some more of the old cab support off.

[Kronald_70GMC]

So it finally happened. I couldnt take it anymore! Flux core was driving me crazy! So I went out and got a gas setup So much nicer! But now Im back at square one....learning to weld again as this seems like a different tequnique is required. Here are some pics of my first go.

[Graham57a]

Dude you are a brave soul for taking on that cab, kudos to you. It looks like you are getting the welding down, honestly the hardest part (in my opinion) with patching is knowing how to get the new metal to fit right and it looks like you have that part down. Are you using anything to seal up the raw metal in some of those pockets before you cover them up?

[Kronald_70GMC]

Originally Posted by Graham57a

Dude you are a brave soul for taking on that cab, kudos to you. It looks like you are getting the welding down, honestly the hardest part (in my opinion) with patching is knowing how to get the new metal to fit right and it looks like you have that part down. Are you using anything to seal up the raw metal in some of those pockets before you cover them up?

Thanks man. It definatly is a huge undertaking. I have been using zinc weld thru coating to seal up the pockets and all the double metal. The trick im working on right now is trying to fix pinholes left from when I was using flux core. Should have just got gas right off the hop. I would be alot further ahead.

[BIGglaSS]

Your repairs are looking good. Chasing pinholes can take forever. If you didn't hammer stretch out the weld seams, that will contribute to the floor becoming crowned. (Though, I have found that reproduction pieces aren't perfect). The long weld seams shrink along the length of the seam. That causes the metal in the center to buckle and crown, because it has no where to go. You can usually hammer out a seam, and only need minimal shrinking in the center. But hey, I understand, that is a hard seam to reach and hammer out. The more experience you get at working and welding sheet metal, you will learn how it behaves.

[Kronald_70GMC]

Originally Posted by BIGglaSS

Your repairs are looking good. Chasing pinholes can take forever. If you didn't hammer stretch out the weld seams, that will contribute to the floor becoming crowned. (Though, I have found that reproduction pieces aren't perfect). The long weld seams shrink along the length of the seam. That causes the metal in the center to buckle and crown, because it has no where to go. You can usually hammer out a seam, and only need minimal shrinking in the center. But hey, I understand, that is a hard seam to reach and hammer out. The more experience you get at working and welding sheet metal, you will learn how it behaves.

Very true. I have already been learning a ton about what the metal does at the seems when welding. Thanks for the read and the compliments.

[Kronald_70GMC]

More good news! We were tearing out a poorly built mezzanine at work yesterday and I scored 2 new light fixtures for the garage. So I called my dad over last night and we got them up. Almost need sunglasses now Just gotta wait for 2 more to turn up somewhere and Im laughing.

As for the truck, Ive been slowly chasing pinholes from the damn flux core Though I did find some time between letting the compressor rest to strip the e coat off of the bottom of the floor pan. Soon enough Ill be cutting out the rest of that rotten support.

[Kronald_70GMC]

Today was a good day! Got the rest of the pinholes filled! Now its on to bigger and better things, aka cutting out the rest of the rotten support. Also found some more light fixtures in our warehouse and the electrican told me if I need them they are mine. So bright I almost need sunglasses now.

[ryans69chevy]

Nice! I like the new shiny metal... make the rest of the floor look like that! Did you get any "oil canning" on that floor pan after you got it all welded in? What's the process of getting your supports in - are you going to have to reinstall the brace from back of cab to front first? Or weld in your supports first?

Btw did you get another blast of winter up there? We did last week and today was below zero with the wind. Thought we were on to the next season...

[Kronald_70GMC]

Originally Posted by ryans69chevy

Nice! I like the new shiny metal... make the rest of the floor look like that! Did you get any "oil canning" on that floor pan after you got it all welded in? What's the process of getting your supports in - are you going to have to reinstall the brace from back of cab to front first? Or weld in your supports first?

Btw did you get another blast of winter up there? We did last week and today was below zero with the wind. Thought we were on to the next season...

Shiny metal is my goal! Lol I did not have any oil canning, just that high hump that I had to shrink down. My plan is to fully repair the floor pans and then install the support as a whole piece.

We did get more winter, not just a blast though. It is like an explosion. We have been breaking 100 year old cold records. Currently as I type this it is -14°, -20° with wind chill.

[ryans69chevy]

Originally Posted by Kronald_70GMC

Shiny metal is my goal! Lol I did not have any oil canning, just that high hump that I had to shrink down. My plan is to fully repair the floor pans and then install the support as a whole piece.

We did get more winter, not just a blast though. It is like an explosion. We have been breaking 100 year old cold records. Currently as I type this it is -14°, -20° with wind chill.

Did you show how you did the shrinking? I need to do that to one of my panels. How did you go about doing that? Shrinking disc? I'm thinking I need to buy one...

That sounds like a good plan for the supports.

Holy cow! That's a bit cold for this time of year I'd say. We are also breaking records for the coldest temp. I need it to warm up so I can get outside and do more sanding!!

[Kronald_70GMC]

Originally Posted by ryans69chevy

Did you show how you did the shrinking? I need to do that to one of my panels. How did you go about doing that? Shrinking disc? I'm thinking I need to buy one...

That sounds like a good plan for the supports.

Holy cow! That's a bit cold for this time of year I'd say. We are also breaking records for the coldest temp. I need it to warm up so I can get outside and do more sanding!!

I think I breifly mentioned how I did the shrinking. Ill try to give you some more detail. I found a video on youtube that showed how to shrink using a propane torch. Basically what you want to do is heat up the high spot with the torch until it just starts to glow pink in the center. Then take your body hammer and a dolly and flatten down your high spot. Then you need a wet rag on hand so you can rapidlly cool the spot. This will shrink down your panel. Then if you end up with a crater, just contine the procedure again always heating the center of your high spot. Hope this helps. If you search how to shrink sheet metal on youtube, there was quite a few videos if I remember correctly.

I also need it to warm up so I can drag the rest of my truck home.

[ryans69chevy]

Originally Posted by Kronald_70GMC

I think I breifly mentioned how I did the shrinking. Ill try to give you some more detail. I found a video on youtube that showed how to shrink using a propane torch. Basically what you want to do is heat up the high spot with the torch until it just starts to glow pink in the center. Then take your body hammer and a dolly and flatten down your high spot. Then you need a wet rag on hand so you can rapidlly cool the spot. This will shrink down your panel. Then if you end up with a crater, just contine the procedure again always heating the center of your high spot. Hope this helps. If you search how to shrink sheet metal on youtube, there was quite a few videos if I remember correctly.

I also need it to warm up so I can drag the rest of my truck home.

So how bad was the high spot before you started shrinking it? Did you try hammer and dolly before shrinking? That's what I've been doing and it's probably my impatience, but I can't seem to get the panel to straighten out. I've thought of getting a shrinking disc but maybe I could try a handheld torch bottle.

[Kronald_70GMC]

Originally Posted by ryans69chevy

So how bad was the high spot before you started shrinking it? Did you try hammer and dolly before shrinking? That's what I've been doing and it's probably my impatience, but I can't seem to get the panel to straighten out. I've thought of getting a shrinking disc but maybe I could try a handheld torch bottle.

I was about 3/8" high. I needed to use heat to do it or It would have been oil canny. And it wont lay flat unless you use heat.

[Kronald_70GMC]

Got some more rust cut off. I started on the passenger side and got most of the rocker cut off and started drilling out the cab support. I also figured that I might as well pull the seat backing plate of and get rid of any rust betweet it and the floor pan before re installing it. Hopefully by next weekend the rest of the cab support is out.

[Kronald_70GMC]

Lots of progress made in the last two days. We are a little slow at work right now so I decided to take an unpaid day off yesterday. Which meant GOODBYE RUSTY CAB SUPPORT well almost. There is about two feet of the rear crossmember left. It is not a fun procedure thats for sure. I ended up having to cut the thing into a bunch of smaller pieces to get the welds to break loose. After all that I decided that the rest of it can stay there until it is in my way. So onto more floor pan replacement. I got the rear section cut out now and I just need to fine tune for fit. There were some minor diffrences between the old and new pieces but I think that was mostly because of a few small changes made to the 71-72 cabs. Anyway I got them all sorted out now. Hopfully Ill have it tacked in place tomorrow evening.