High build primer

[tflnemesis]

Hi All, can anyone give me some idea of the gap filling properties of high build primer?

I'm not talking 10s of mm, maybe half a mm at most.

I have some 3d prints I want to spray up but the surfaces are textured (due to the printing method).

My problem is that several of these pieces need to be glued together so I don't want to over sand them to give me a poor fit up, also once glued they are going to be an absolute pig to get into all the nooks and crannys to sand.

I am hoping that I can lightly sand my pieces, glue them together then use high build primer to even the surfaces out so that a light sanding of the cured primer will leave a fairly smooth surface.

Your thoughts? Richard

 

[Dcal]

What plastic are they printed with?
You will probably need a plastic primer under the primer to ensure adhesion.
Any hi-build primer will get you a coating 0.5mm thick but you will end up with a finish the same as you started with if you put it all on in one coat.
As long as you can sand it back you should get good results. Sanding into creases will be no fun.
Depending on how fussy you need to be, a guide coat will help in ensuring you get a good flat finish.

I use Max Meyer HS top filler (2K Acrylic) You can adjust the thinners to get the filling and flow properties you want.

Any good 2K primer should do the job.

 

[tflnemesis]

Thanks Dcal, just what I was hoping for, my model is going to be an E11 stormtrooper rifle .
They are printed with PLA, I haven't looked at what I might need to get the paint to stick yet as I have another 3-4 days of printing before I will have all my parts. I am just trying to get a picture of how much finishing I will have to do before it comes to gluing and painting.
I did briefly toy with the idea of dipping all the parts in epoxy but that will get expensive purely because of the size of it.

Its going to be a rattlecan job as I am not set up for air spraying.

 

[Dcal]

Rattle can will probably be 1K (you can get 2K rattle cans) but they are mostly thinners so will take more coats.
It will also take longer to dry fully (through dry) to get a decent thickness that you can sand off.

Painting or rolling will get more paint on but you will also have more to sand off.
It will be easier to sand than the dipped epoxy though, just take longer.

 

[8ob]

Why not just flat down the print, its probably going to be less work than trying to hide the rough pla finish by drowning it in paint.

Bob

 

[steveo3002]

id say you have the wrong idea for primer

whatever you use even if its mega build will still sanding to shape after its dry , so i would suggest 180/240 the part until its a nice as possible , then plastic primer , then high build , let that set a few days and then sand it 600/800 , might need to re prime and do it again until its perfect

 

[ajlelectronics]

id say you have the wrong idea for primer

whatever you use even if its mega build will still sanding to shape after its dry , so i would suggest 180/240 the part until its a nice as possible , then plastic primer , then high build , let that set a few days and then sand it 600/800 , might need to re prime and do it again until its perfect

Another option is to Diamond Glaze it, but it will still need sanding flat.

 

[Dcal]

Agree with @steveo3002 and @8ob but I don't know what PLA sands like or how it paints, it might get a bit hairy with the sandpaper which will then need to be locked into the primer and sanded out before going again.

A rattle can doesn't seem like the right tool for the job if you need high build, so I agree get it at good as you can before painting.

Could you keep the printed effect and use it as a feature?

As @ajlelectronics has just said you could diamond glaze it but don't know how that will stick to PLA.
There are similar products for use on top of plastic but they might be harder to sand

 

[ajlelectronics]

Well for plastics you have two options that work for certain, plastic primer or epoxy primer (my suggestion).

 

[tflnemesis]

Thank you all for your input.

I know I have a lot of sanding to do, unfortunately most by hand as there aren't many flat surfaces I can get to with a power sander.

I was just hoping that I could get the parts somewhere close to the finish I want and then smooth it out with the primer and flat it back to a decent finish.
Looking through some of the cosplay and modelling forums where people have made similar and wanted a smooth machined like finish they have used a spray filler, then continued sanding to achieve the finish. I assumed that they meant high build primer as I haven't come across spray filler.

Still considering my options at the moment, being a geek never makes for easy jobs .

 

[tflnemesis]

Oh btw this is the E-11 stormtrooper rifle that I am printing:

https://www.thingiverse.com/thing:2415489

 

[carbon]

Spray filler is available but if your not set up for spraying it may not be a really suitable.
https://www.spraygunsdirect.co.uk/i...pray-filler-1-litre.html#sthash.mWTsDm9P.dpbs
Other brands may be available but first one I found

 

[tflnemesis]

Thanks carbon, I have found some rattle cans of spray filler on amazon:

https://www.amazon.co.uk/Filler-Spr...&qid=1549117776&sr=8-10&keywords=spray+filler

I have got some print failures I can test it on before I try with my model.

 

[Dcal]

Certainly worth a try, just make sure it's fully dry before sanding, leaving it some where nice and warm (hot press?) will speed things along.

 

[ajlelectronics]

You still need an adhesion promoter over plastic.

 

[tflnemesis]

You still need an adhesion promoter over plastic.

Popped into the local gaming shop today as I was in town with SWMBO, they have planety of plastic primers for me to have a try with.

 

[fizzy]

I have read of people using acetone vapour etc to smooth out 3d prints

 

[carbon]

Acetone only works for abs prints, but does produce a smooth finish with smaller layer heights