bushing vs reduction piece

[ste hughes]

hi guys

building my first MAPP cannon

i have 1 cannon thats powered by hairspray which is awesome but the way i went down from 4" to 2" was pieces of plywood screwed and glued together

its not failed once!

but i dont want to go ghetto with this next cannon

problem is though i can't find a reduction piece that will go from 4" to 2" in the uk - the most it will reduce is 4" to 3" and this piece is about £30 ($50) plus the price of a bushing

so would i be ok if i use a 4" to 2.5" bushing and then use another bushing to take me down to 2"? this will cost me about £10 - that £20 i can spend on paint to make it look awesome

is this likely to be a problem - it will be properly glued and screwed just to make sure

thanks

[Crna Legija]

as long as the parts you use are pressure rated to 120ish psi it would be fine

[jackssmirkingrevenge]

The plywood and glue approach isn't actually what I would consider ghetto, au contraire it's a cheap and neat solution if done properly

Pretty much what I did with my last large combustion, though it was mostly epoxy based.

[Gaderelguitarist]

My two working combustions actually utilize wooden plugs to seal off the chamber. If done correctly, it can be a completely reliable build. This actually reminds me that I need to post one of those two on here. I'm rambling...

To answer your question though, yes.