Thread: Why isn't a 100mm dust port 100mm?

Originally Posted by OtakiriLad

I am taking on board everyone's comments and will attempt to form a smooth 'bell-mouth' out of 150mm PVC over the next while. I have used a similar method to John's with a shaped wooden former and forcing it into the PVC pipe while heating the pipe with a heat-gun. This is a slowish process but does seem to work.

A dumb question while I think about it. Has anyone tried making these types of housings in full or in part using paper mache method maybe with a fibreglass outer?

Interesting that I discussed doing just that with someone last year. It's fairly easy making a bell mouth entry if you have a woodworking lathe and some sort I face plate. I use 32 mm or a 2 x 18 mm MDF sandwich. Once the wood is ready I can turn one up in about 20 minutes - this includes a small recess at the back for the flush internal attachment of short section of 150 mm diam pipe.

Originally Posted by OtakiriLad

I am taking on board everyone's comments and will attempt to form a smooth 'bell-mouth' out of 150mm PVC over the next while. I have used a similar method to John's with a shaped wooden former and forcing it into the PVC pipe while heating the pipe with a heat-gun. This is a slowish process but does seem to work.

A dumb question while I think about it. Has anyone tried making these types of housings in full or in part using paper mache method maybe with a fibreglass outer?

At the same time I will be working on making up a 150mm fitting for the impeller to replace the existing 130/125 inlet. Then I can slowly work between the two ends introducing pipe, short lengths of flexi as joiners, home-made wyes, and home-made blast gates and experimenting with different variations along the way. I will post progress with photos as and when.

Hey OtakiriLad. Have a look at the Fibreglass Cyclone Project thread and you'll see some 6" fibreglass machine intakes which I've produced. The latest one on the thread for the jointer was quite involved, but a simple former can be knocked up with polystyrene foam, fine tuned with builders bog or gypsum plaster and then covered with packaging tape or pvc tape to stop it sticking. Slap on the fibreglass and dig out the poly from inside when its cured and you're done.

For what it's worth here is a link to some of my thermoforming exploits. I've only ever used a heat gun, never tried oil.

Many thanks guys. I will be taking as much of these suggestions on board as I can. I have started upgrading the DC as per the 'Eat My Dust' thread and conversion of machines is next.
Cheers

Originally Posted by OtakiriLad

Many thanks guys. I will be taking as much of these suggestions on board as I can. I have started upgrading the DC as per the 'Eat My Dust' thread and conversion of machines is next.
Cheers

My 2 cents to answer the original question....this irritate me on my gear too.

I found that every single one of my "100mm" holes were different. I solved it by eating some 3AM vanilla yoghurt (yum!) then washing the container and slicing the bottom out. The container has a handy opening of 117mm with a tough ring. The container tapers so it plugs easily onto the outside of the socket, then the 100mm hose or connector slides easily over the bottom.

The taper on the inside holds solidly and after carefully removing about 1" up from the bottom of the container all the adapters slide over the outside. It makes a super snug connection on both ends. Just press on and twist off.

Easy

On the matter of thermo forming.
I see no need to use oil, boiling water is plenty hot enough and makes less mess.

a metal bucket or a big glass or non plastic mixing bowl from the kitchen is nore than enough.

Just boil the jug a few tomes then fille er up.

I supose an electric urn or crockpot would be good if you where doing a bit.

Anybody who was in the electrical trades before the introduction of corigated conduit will be only too well familiar with thermo forming PVC.

Any sorce of heat will work with greater or lesser sucess.....I was taught using an LPG burner, I frequently use a heat gun, I have been known to use the kitchen stove.
BUT bay far the best is boiling water.....it gives so much better control for end pieces.

You can control how much of the pipe you want softened...quite accurately, by how deep you put the pipe in the water and you get a more even heating than any other method....some patience is required and sometimes a second boiling of the jug.

with the 100mm plumbing pipe you can make it fit to almost any dust spout that is close...by.....heating up the pipe , slipping it onto the spout in question and quickly while it is hot...tightening up a hose clamp or two on it.

This will give a snug fit every time...under or over sized fit.

you can then standardise using flexible dust hose joiners cut in half.....buy the loiners where you buy the hose..so hopefully they will fit.....the joiner can then be glued into the PVC pipe....if the fit is not snug....thermo form it.

100mm pipe is a bit big to bend curves in.....but with a bit of practice realy good smooth free flowing curves can be bent in 32mm electrical conduit ( compatable with many vacuum cleaners hoses) and 50mm electrcal conduit (good for the bigger vacuum cleaner type jobs).

with a bit of practice you can make all sorts of interesting shapes and realy smooth transitions with PVC pipe and a bit of heat.

On the matter of 150mm pipe....yeh wel I know that it flows better......but putting 150mm dust connections on lots of machines is entiely pointless, because the facilities on the machine will not flow what a 100mm hose will.
AND even with the existing flow the extraction is effective.

The 6X9 belt disk is a very good example......I have a 100mm connection split (buy a thermofromed adaptor) into 2 x 2 inch hoses connected to the more or less standard connections.....and it misses very little that gets into the hoods.
These low speed sanders carry the dust into the hood.....so very modest air flow works.....more airflow does bugger all.
One of the reasons for dust going else where on these units is material getting stuck to the belt and falling off later in the cycle after the belt has been thru the hood..no amount of air flow will help that.

I have a 12 inch 1 Hp sander....I have opened up the factory 100mm connection considerably.....but the body of the sander continues to be the restriction.....you can hear this when the hose ie connected or disconnected.
Still any dust that gets into the hood is captured......dust that does not get into the hood is not..and never will be regardless of the flow.
SO, I generally sand so the waste is projected into the hood.

In my case I have found that doing more work on the collection facilities and getting the gaps closer will result in better capture with less need for high air flow.
That and keeping the hoses and ducts short.

cheers

Originally Posted by soundman

On the matter of 150mm pipe....yeh wel I know that it flows better......but putting 150mm dust connections on lots of machines is entiely pointless, because the facilities on the machine will not flow what a 100mm hose will.
AND even with the existing flow the extraction is effective.

Correct, but only for those machines that will not allow us to pull enough air through the machine or into the hood. Every shop is different, but in mine the only machine not hooked up to a 150 mm port is the jointer/thicknesser. Looking at a few mods right now. Time will tell.

The dust collection works well on every other machine. The linisher was my dirtiest machine when it had a 100 mm port. Now it is one of the cleanest, even when sanding on the wheel. The trick was to create hoods that worked well in conjunction with 150 mm ports. Also, for the linisher, pulling some air from an extension that runs along the back (returning belt) helped pick up the last of the dust.

Cheerio!

John