Rising Putty,,,, Need advice

[AMDman13]

I know Bones was having trouble with this when he was painting his cab... I am running into the same problem.. My cab has been in the sanding smooth stage for over two weeks now and each time I get it smooth the next day they have risen again. I know that humidity is not the issue because I live in the god forsaken desert of Phx AZ where it has been dry and a 110 for the last 2 weeks.

I guess what I am asking is will it ever stop trying to work it's way out of the counter sinks? I would hate to paint, so that two weeks later they begin to show their ugly pimple heads again..

I'm half tempted to drill it all out and use an epoxy bondo. Too bad I didn't learn about this until after the fact.

[Bones]

This happened to me on something like 6 coats (both undercoat/primer and final overcoat). I still have no idea the exact reasons but it was damn frustrating. I just kept sanding it back and repainting it until it stopped.

Sorry... not much help here.

[Buddabing]

Maybe living in too -dry- a climate is the problem. I live where it is very humid and I never had this problem.

I would say either "F it, it doesn't matter" and leave the slight bump or dig out the putty and bondo it. Waiting for it to swell up and worrying about it is too much mental anguish.

[somunny]

MM,

Did you decide against the laminate?  If so, I think Bud's suggestion about the bondo sounds like a good alternative.

Steve

[MYX]

Perhaps too late now, but I stopped using putty and started using Bondo as it was far easier to work with both in it's wet state and awesome once it set up. Plus you mix it, smear it, and can be sanding it within a half hour. I have not had any issues with it rising like I did with the wood putty.

[Hiub1]

Myx is spot on. Wood putty is awful. Bondo takes a tad more work to brew, but once its on there, its very strong, and doesn't expand over time like putty does.

[Minwah]

I had this too....I'm gonna scrape the filler out and try some car body filler - just hope it won't crack and fall out when moving the cab.

[Nannuu]

I'll suggest bondo as well.  I won't touch putty anymore after having that exact same problem.  Bondo is GREAT.

[Dervacumen]

What kind of Bondo do you use?  I've never used it and there seems to be many options, none of which is for wood.  At least I didn't see any.  Probably missed it?

[Hiub1]

Bondo brand automotive plastic filler will do. Other supplies that you will need are: A plastic bondo spreader, and a cheese grater is optional but well worth it to me. Hm... I smell a bondo FAQ coming!

[Buddabing]

There's no wiki entry for bondo......this must be remedied.....

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[Hiub1]

I smell a bondo FAQ coming!

Change that to a Bondo Wiki entry!

[Buddabing]

I added a bondo wiki entry which describes what bondo is and what it is used for, but not how to use it. Someone with bondo experience should complete the entry.

[Hiub1]

I will take care of it later tonight.

[MYX]

I did not use the automotive version. I used the other one in the blue can. It was more for house type stuff. As I understand it, the auto version has fiberglass fibers in it. I used the blue stuff and it worked better than great. I want to make a whole cab out of the stuff. Well perhaps not. 

[psychopanda]

I went with the automotive Bondo version, but have no experience with the other type.

One thing I'll mention though, circle the area you are going to Bondo with a sharpie (I used red) beforehand. After the Bondo dries sand lightly until you start to see the sharpie line. It's a good way of letting you know if you've sanded too much or not enough, because the sharpie mark will actually become visible through the Bondo as you sand close enough.

Edit: last sentence to make it more clear

[AMDman13]

somunny,

I decided not to use laminate for a couple of reasons. Originally I was planning to paint and I had finished 85% of the build before I started to consider it.   I thought it would be too expensive at first. Then however I found a local WilsonArt warehouse who sells the Matte black for like 19.00 a sheet. The cab is impossible to completely disassemble as it is built out of glue with screws and brad nails. .
This would leave me to only laminate the outsides and I was worried about bowing since I would only be able to do 1 side.

The putty seems to have leveled off now, but it has been a total pain to work with. Over the last couple of weeks it has either risen or I have sanded too much and left a divot..  I'm about ready to push it out into the driveway and run it over a couple of times

Bondo is sounding interesting since it only takes like 30 min to dry. Might not be so bad to do over. Also the sharpie idea is great.

[MYX]

It does not so much as dry as finish it's chemical reaction. You can sand befor that but you will end up with a big glob of goo on your sander. 

[MYX]

Added Bondo Instructions to the wiki.

[psychopanda]

Great instructions on the wiki. I use a metal putty knife to apply Bondo once mixed. Right after I've applied the Bondo, I quickly wipe off the excess with some scrap paper or whatever. I tried plastic putty knifes the first time around, but the Bondo stuck to them and I wasn't able to get a smooth application the next time. The smoother you apply the Bondo, the easier it is to clean up with one sanding.

The only caution about using Bondo, is don't get it on you and watch for the fumes/dust when using it. It's really strong. Other than that it's great once you get used to it.

[MYX]

O gotta find the site tonight, (It may be Muhati's site) but someone has a tutorial about a similar substance to bondo but it is much thinner and can be used on surface problems. It is still an epoxy type mix but thin like thick syrup. apparently you can get near razor thin and then the sanding is really a breeze. (II personally have not tried the stuff but am very interested).

I have used and like a metal putty knife as well. I will add that to the WIKI.

[Hiub1]

Metal is not smart. If you let the bondo adhere to the metal, it will be stuck on there permanently. The advantage the plastic one has is that you can leave a bit of bondo accumulated on the edge and you can peel it off with no residue. Also, a useful thing to have is a cheese grater. You can add more than enough bondo, without being smooth with it to whatever you are patching, and about 5 minutes after curing you can cheese grate the excess until you are somewhat smooth. After it dries, then you can sand and you should not have much excess bondo to start sanding with. i'll take a pic of one when I get home.

[AMDman13]

For the most part my old putty seems to be okay.. However "the most part" is not good enough for me! There are a few parts that had still risen even today. It's been almost 3 weeks now...
I don't want to spend forever trying to dig these out... I have to admit to something I tried awile back...Some I redid and mixed the putty with tightbound wood glue.  I thought it might help. Anyway their in good!

What if I just sanded it enough to make a slight divot in the putty and then a thin layer of Bondo??? Any thoughts?

[psychopanda]

Metal is not smart. If you let the bondo adhere to the metal, it will be stuck on there permanently. The advantage the plastic one has is that you can leave a bit of bondo accumulated on the edge and you can peel it off with no residue.

I had the opposite experience with metal versus plastic. With the metal putty knife I was able to wipe off most of the Bondo before it dries and still sand or chip away anything left over. The plastic putty knife ended up getting damaged when I tried to remove the Bondo later, and then left big grooves the next time I went to apply Bondo.

Thanks for the explanation about the cheese grater, I was wondering why people were suggesting that.

Marlboroman13, sorry I've never tried it, so I'm not sure what would happen. You're probably better off starting over with Bondo and saving some time in the long run.

[MYX]

I got bondo stuck to my putty knife, but sanded it off with my electric sander in about 10 seconds.