of the two is one better than the other?
will they leave oil marks on the paint?is that from touching it?if you get oil marks how do you get that off?does it matter what color the blu tack is
i have used silly putty before in small areas so i did not have issues but it did move a bit when left in place and did have it on some grills....dont do that. thanks for the help

Blu Tac doesn't flow like silly putty and I have used it without issue, you do however need to be careful of small parts as it will pull them off if care is not taken.

I have not used silly putty, but use blue-tack alot. I prefer the Staples/Business Depot brand, find it is not as tacky at some other, but still leaves a good line. I also use it to hold items I am painting. I cut up old sprues, stick a piece of sticky tac to the end, then stick what ever I am painting or airbrushing on to it.

I tend to use silly putty to mask off paint schemes. The reason for this is that it is very easy to shape- and you can use your hands or a cocktail stick etc to get nice, fine demarcations in pretty much any shape rather quickly. I've never found it to leave any residue. The odd tiny bit will get stuck but just stick a smaller blob over it and it will lift it off. Silly Putty also tends to stick to things if it flows- it will kind of droop gradually if left hanging off a surface (like off the bottom of a side skirt for example) and will stick to whatever is beneath- table, paint booth etc. It usually comes away pretty easily though, but it can be liable to pull the scheme out of shape too if you are not careful.

The biggest problem I have with silly putty is when using it on, over or near photo etch- it loves to rip it off and get stuck in PE grilles. A good way to stop this is to put a bit of tape over the PE parts before laying the putty over them and go back and airbrush the parts later.

I don't tend to mask with blu tac as I find it takes longer to shape it well and I also find it can stick stubbornly in small holes and crevices. Like Kevin I find it useful to hold small or awkward parts on cocktail sticks. I just use the branded stuff and I've never had it leave any residue or anything.

I use blu-tac or similar products - it is harder to shape than silly putty but i eventually manage, and it stays round instead of deforming as silly putty does.

also it is a lot cheaper.

I've tried silly putty and was less than pleased with the result. It seemed to shrink after I applied it. Blu tac may be a little more difficult to shape, but it does not deform.

Blu-tak all the way. I buy it at the dollar store and the cheap stuff works great. The other guys have mentioned the dangers of Silly Putty.
I use Blu-Tak for subtractive masking - I shoot the color, then cover the areas with Blu - Tak that I want to remain that color. Then I shoot the next color and repeat. After I shoot the last color, I remove all the Blu - Tak to reveal the finished camouflage pattern.
That's how I did the complicated pattern on this H35. This is all airbrushed. The black demarcation lines were done last with a technical marker.

thanks for all the info on both products i have a few cards primed and base coated so ill get both and see what one works the best for me