expanding foam and steel frame

[Gytis]

Hi,

I read somewhere if you fill the steel box with expanding foam it will helps a little to avoid vibration and everything else associated with it?
It is true or just a myth?, anyone tried it?

I am also interested in this one product :
http://www.youtube.com/watch?v=h1P4L7TwV9Q&feature=player_embedded

Cheers

Gytis

[ptjw7uk]

works on car bonnets and door skins so should work!
But I think its only low frequency noise that it works on.

Peter

[JAZZCNC]

No it add's very little resonance dampening to thicker steel, ok on thin sheet and better than nothing but only just.!!

Best way I've found is to use kiln dried sand, the stuff they sell for brushing in top block paving.
Seal ends, (expanding foam works here.!) with plates and put large hole at top & bottom for filling/emptying quite easy and makes big difference to vibrations and resonance coming from machine, plus it won't try walk off when shit it''s fan. . Lol (Those that have built and got it wrong will understand. . :hopelessness:)

[mekanik]

CNCCookbook: Epoxy Granite Fill (http://www.cnccookbook.com/CCMillEpoxyFill.htm)

[JAZZCNC]

CNCCookbook: Epoxy Granite Fill (http://www.cnccookbook.com/CCMillEpoxyFill.htm)


To foooooking expensive.!!!

[mekanik]

Hi jazz
Just remembered i had that bookmarked so posted it as it might have been usefull, it's a long while since i had a look @ it and as i recall it got a bit too involved and made my head hurt, the guys were experimenting with various aggregate and resins, i think it could be usefull to deaden the vibration in the main frame but think it would probably be a bit on the heavy side for the gantry

[JAZZCNC]

Hi jazz
Just remembered i had that bookmarked so posted it as it might have been usefull, it's a long while since i had a look @ it and as i recall it got a bit too involved and made my head hurt, the guys were experimenting with various aggregate and resins, i think it could be usefull to deaden the vibration in the main frame but think it would probably be a bit on the heavy side for the gantry

Yep it's great at deadening vibration and my next machine which is soon to be built will incorporate some of it.!!. . . But it's just too expensive for filling frames etc and sand works just has good and can be removed if needed.

On that note if anyone knows a place to buy cheap Epoxy resin in reasonable sized qty's 25lt + then I would like to know please.

[mekanik]

have a search for polystyrene resin it's considerably cheaper than epoxy resin.I had a bash @ Infusion transfer a while ago and used it for prototyping.the West Epoxy costs a fortune. try east coast fibreglass supplies, also if your using it for mixing with aggregate the stuff used by roofers might be cheaper

[Swarfing]

Years ago a company i worked with a company that used to repair failed screeds. This was done with an epoxy resin, the difference was it was very thin and just poured over the sandy screed. It soaked in and set hard fixing the problem. Now what you can do is partly similar to Jazz's suggestion. Take some granite chippings (or pea shingle) and mix this with silica sand as your base. Use some epoxy resin and thin it down with automotive thinners and ram it down the tubes. Or fill the tube with the dry mix and add the liquid (do it in small sections). This will give you the result you want at a reasonable cost. Now the reality is you are filling a tube so the type of resin does not really matter and ordinary fibre glass resin will do.

[JAZZCNC]

Eh bouncy Tit's why has your name changed.?

That's a good point about any old resin will do and I hadn't though about it like that but still any resin isn't cheap and the dry sand comes out if needed that's why I like it. Thou I can see the benefits for some areas like hollow Gantry's.!!

[Swarfing]

Had to change as the name did not fit the tits...LOL! At the end of the day if it is going to stay you can fill it with any old Sh*t if a resin is involved? you even add foam beads to the stone ballast to cut down the weight if needed.

[Gytis]

Thanks guys for the info

Ok.., it seems that expanding foam will not work, I'll go with sand, just one question,
I have to fill with sand whole frame + bed?, or just frame sides?