Spraying gravitex with the pipe attachment

[Flapdisk]

The gun I bought (Which screws directly onto the gravitex bottle) also has a length of plastic pipe with a nozzle on the end for getting into sills and chassis members, but when I attach it nothing sprays out the pipe except air? I tried thinning the gravitex a bit and still nothing, but I didn't want to thin it too much as it will run all over the place.
Anyone any experience of this please?

 

[Cobbler]

I think you will find that the gun is for spraying waxoyl or similar anti rust fluid. For gravitex the gun uses a nozzle about 2 inches inches long. I may be wrong, but I think the gun itself is the same, just a different fitting. If you look on ebay you will see both types.

 

[MG David]

Stone chip like gravitex is thicker than waxoyl. It is not intended for injecting into sills. So sending it up a long narrow pipe will not work. If you want to put something inside the sill use a cavity wax like waxoyle or one of the others.

 

[Flapdisk]

Ahhh ok, thanks guys, my gun sprays the gravitex fine with just the normal nozzle on, I have already sprayed the underneath of the car with it.

 

[Wallace]

If it's one of these, as Cobbler says the tube is for wax injection. I had a gun supplied free with the Gravitex and even though I have an older identical gun it had been used for bitumen based underseal so decided to use the new one to avoid contamination but the new gun gave me problems. Turned out the nozzle was Loctited in place 3mm short of bottoming out and there was no bleed hole in the can mounting flange so it really threw a thick coating on in fits and starts. Once the bleed hole was added and the nozzle sorted it was fine.

 

[Flapdisk]

That's the one Wall. I was stood there with the tube inside the sill, pulled the trigger and it squirted out the bleed hole on the flange straight in my face That stuff doesn't half sting on your skin. Seems strange that it won't go down the quarter inch plastic pipe, but will spray out of the 1mm bleed hole

 

[Wallace]

(Must not laugh, must not laugh!)

That gun drove me mad as it was also the first time I had used Gravitex so I was not sure if was me, the gun or the Gravitex. I managed a reasonable finish but it was really thick, so thick in fact that Mig fillet welds completely disappeared beneath it but there were no runs or sagging. Wthin 10 minutes a reaction started in a couple of places with the epoxy mastic it was sprayed over lifting it like paint stripper as the solvent could not flash off. I tried a blast with the heat gun to dry it off quicker and that made it worse, it stripped quicker and spread further! Best paint stripper I have ever seen.

Luckily I had only done a small area over the repairs I had made but the gun had flobbed a whole litre on and I ended up taking the whole floorpan back to bare metal to get an even finish. Before using the flobby gun again I sprayed a few lighter coats on with a gravity fed spraygun and let that dry as a barrier coat, the Gravitex was fine after that.

 

[Flapdisk]

Bummer mate, I hate it when something ruins the work like that. I had taken the underneath of the car to bare metal and sprayed it with a few coats of epoxy which I left for a week or two before spraying the gravitex. I was surprised at how fast it came out the gun and had to work fast so as not to get huge build ups. But you are certainly right, a couple of coats and it covers everything, it dries nicely too with a lot of the marks going when it's dry, just looks like the underneath of the car has had a big sheet of rubber melted over it . Luckily, after removing the plastic trims which are on the top of the sills in each doorway, making a sort of plastic step to protect the sill, I have a row of 1cm holes along the top which I just stuck the normal nozzle in and swiveled to all angles and then moved to the next hole and repeated and I think it's given the inside of the sills a good coat, certainly more than if I hadn't done it, and it was dripping out the drains at the bottom of the sills, so I reckon the areas where water would sit if it got in is protected.
Also that gun powers it out with such force I recon it will have got in all the corners inside. I hope so anyway. I recon it will outlast me :-)