Duraglass filler troubles

[oldmanmark]

First time with a filler. Open the can to stir and was to thick to stir. This is before adding hardener. Im ignorant, don't know what to expect. Cans been on shelf for 6 months or so. Maybe thats the problem, old filler started to dry and harden.
When mixed with hardener didn't spread smooth. Rough surface. Im sure there wasn't excess of hardener. Again i don't know what to expect. Watched some youtube vid tonight. Something is wrong, think the can is to old. Metal was clean with a good tooth to adhere. How to salvage this and finish? A lot of sanding to metal? Concerned about air pockets, etc. Its a large area above left rear wheel well arch where car was hit when P.O. had it and the lower section to the B pillar. 2 pieces of good metal are butt welded together with visible welding warp to smooth out. Going to buy fresh can and hardener.

[Air-Cooled Head]

Was there a question here?
Old filler will harden and some will begin to crystallize if left on the shelf long enough. Don't think 6 months is long enough.
Duraglass is rather thick out of the can. You can't really "stir" it, in the typical sense like stirring paint.
Mixing filler is part science, part magic. You'll have to experiment some to find just the right ratio of harder to filler. Then you have to adjust for environmental conditions (hot/dry=hardens faster, humid=hardens slower).
Yep, if you didn't get it on right, you'll need to sand it away and start over. In such a case, I'd use 80 grit and carefully sand to bare metal. That will handle your air pocket concerns.
Yes, a new can of filler & catalyst, and some practice is what you need.
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[oldmanmark]

Air-cooled head, I think theres several ?'s here. which you have answered, thank you. Its a given mixing hardener and filler is experience based. In a youtube vid the same duraglass was much more pliable and thinner out of the can. Confusing. I think my environment is a factor. Ordered new can of filler. Sanding this will not be pretty.

[jspbtown]

And duraglass will not give you a finished surface to paint really in my opinion.

[56bugdan]

I've never actually used it but I thought you had to top coat it with another thin coat of filler. Maybe a couple good coats of sealer primer would work though. I've seen guys use it and it is generally thick and not as workable as regular filler but it sounds like yours is worse than what it should be. Was your can of Filler ever exposed to freezing temps? I don't think any fillers are supposed to be exposed to freezing temps but some react worse than others. Either way I think you're going to be stuck with cleaning off what's there unfortunately.

[buguy]

Yes, most likely its an old can. Do yourself a favor and use some 36 grit on a DA or even a little 3" angle grinder. Duraglass does NOT sand well. It will be quicker to get the shitty stuff out and do it over than it will be to try and get it out nicely. Also, you can add a little fiberglass resin hardener to get the old stuff to smooth out and be useable, but id toss it myself.

Keep in mind duraglass sets up super fast, so you dont have much work time.

Here is a little tip that may help you. When I use duraglass (and I use it a lot), I spread it, then get some 36 grit long board paper and cut it to the size of block your sanding with. Put it on, and just as the duraglass is starting to set up, you have like 1-2 minutes of work time where that 36 grit will shave it down and shape it nicely. I work it over quickly to get it close, then let it harden and finish with 80 grit. Usually one minute of work with a block and 36 grit shaves it down nicely and leaves it very close to finished. And as was already said, you will need to follow up with some regular filler or glazing putty over it. But be ready. It hardens very quickly, so have your shit ready, and dont mix it til your right next to the repair. Spread smaller areas if you need to, so its spread nicer. Like I said, it doesnt sand easily, so the better you spread, the less work to finish. Better to spread more smaller areas then to try to do too much and it hardens on you.

[oldmanmark]

I went back today and roughed the surface of duralast down with the angle grinder, orbital sander then hand with 50 grit. Ton of dust. Im going by the' how to 'in the sticky. I mixed up another wad of filler and hardener and addressed the highs and lows. Discovered the filler touching the inside the can was much firmer and not workable. The rest of the can was workable. Pretty satisfied with the work today. Got another can on order. Will use it to level out more . Then use Feather-Rite to finish off just like in the sticky.
Yup sets up real fast. Being new to filler, ignorance is bliss. Buguy I know what you mean about hitting the duraglass just before its sets up with some corse grit paper. I kept track of the setup time buy sticking my finger nail in the surface excess and try to chip it. When I could not get a chip but could a tiny groove with my nail i started to sand the 'spreader tracks' down. Also got a better spreader and sanded a rounded edge on one side and worked much better. Yes gotta work fast. Good advice from all, thanks.

[oldmanmark]

update...fresh can of duraglass is very soft and pliable.

[buguy]

Weather should be just right for that work too! I was going to mention before too that you can use a 2k poly primer to eliminate having to reskim the duraglass with filler. Poly also locks down any body work really really well. Doesnt let it bleed through. Good stuff and a huge time saver. You have to have a gun with a big tip, but its worth it. I prefer Evercoat Slick Sand, but if there some bare metal spots, its better to use Evercoat Superbuild. You can even wetsand this and paint it if you wanted to, but I prefer to seal it first.