Veneer supplies pump (140rnd db2) - manual

[andrew whicker]

Hi,

My flip top table system was bought used and the previous owner had the above pump. I suddenly lost the ability to get vacuum in the system and I can't find a leak in the system. It would have to be a big leak.

I ran the pump continuously over night, took out a project put in another project, turned the pump back on it only got up to 7 in hg.
Basically it's not even getting close to a proper vacuum.

I let it sit over this weekend. Still no bueno. I have checked and re checked for leaks.

I can't find any documentation on this freaking pump. All I can do is put my thumb over the inlet and watch it pull a proper vacuum... I'm not sure if this is enough information to decide if it's not a problem.

I get a nagging feeling that the pump is leaking internally. I'm about to start taking it apart.. But I'm pretty sure I'll need new gaskets if I do...

Is there a manual for this thing? Something?

(oil less rocking piston pump, 2015 mfg date)

[andrew whicker]

I found I can put a piece of chalk into the table hole and plug the line up to the table completely enough to get 20 in hg.

Sorry, numbers above are for inches mercury... I'll update.

[andrew whicker]

Trying to do this from my phone... Website isn't great on phone and I guess I magically deleted my previous post..

Anyway, 7 in hg is basically nothing. I get 5 in hg when I run the vacuum with the flip top wide open.

The needle reads 7 ish when I half plug the table hole (don't plug the air flow grooves). Ie. There's a huge leak in here somewhere

[andrew whicker]

From memory my system was normally at 12 ish in hg and that seemed really strong

[andrew whicker]

I blew up the bag with my air compressor (partially). My line has a one way valve in it so that was useful.

I put some body weight on it and couldn't see or hear any deflation.. Considering how big of a leak I would have to have, I think I can safely rule out all the lines downstream of the one way valve.

I'm really thinking compressor

[Richard Coers]

I seriously doubt that pump has a 100% duty cycle for running overnight. My guess is that the seals are shot. I've never heard of a rocking piston pump. I've heard them called wobble pumps, but not rocking. I'm sure the seals are burnt up.

[andrew whicker]

There was some hardened crap on the cylinder walls. Nothing crazy. Cleaned with 0000 steel wool. Still no pressure.

Going to look for new piston gaskets / rings and reed valves.

Otherwise it looked in fine shape

[andrew whicker]

The description / marketing says it can run continuously, but yeah. You're probably right.

I pushed my luck.

[Kevin Jenness]

If you can pull 20 in. hg by plugging the line the (major) problem is not the pump. 20in. is enough to do the job. 12 in. is not good at all. My system is set to run at 21-24 in. hg. If you are showing 5 in. with the press open you may have a blockage in the line. It could be a combination of problems.

I don't know what the piston/cylinder tolerances are for a pump like that, and what's done is done, but I would not go at it with steel wool as a first choice. Is there an inlet filter on the pump?

You mentioned a flip top table system and then a bag. If it's a frame press has the gasket come loose or torn? If a bag, what type of closure does it have? Is there a loose fitting inline or a dump valve partly open? It doesn't take a huge hole to have a partial vacuum situation. If you have a partial line blockage reducing the flow rate plus a minor leak in the press itself that might explain the problem.

Sometimes you can find a leak by pulling a vacuum then shutting everything off and listening for a hiss. Another pair of ears may help. Another way is to paint food coloring or use a smoke candle on suspected leak areas. You can get pinholes at creases or from unprotected sharp corners of layups inside the press. How about posting some photos?

Is your system meant to run continuously or does it have a pressure switch? If it is set up and rated for continuous run, the one way valve is superfluous and could be a problem in itself if not opening completely. If it is a spring check valve does it rob any power from the pump to keep it open? My rotary vane Gast pump is ok to run continuously but I do have a pressure switch and solenoid check valve for economy, noise and wear reasons.

I hope you didn't lose a layup- that would be a real pain.

[andrew whicker]

Kevin,

What does your pump pull at the pump inlet when you plug it?

I'm not that impressed that at basically zero volume it can pull a vacuum. I really have tried looking everywhere for a leak and besides a few pin holes that have probably been there forever I can't see any holes near where I put the previous project. Furthermore, just the idea that all I did was open my press up, take out a project, put a new project in and close the table leads me to believe that the pump is the issue.

I can't remember checking the pressure before turning the pump off and opening up the table, but I'm betting if I looked I would have seen the pressure had dropped off during the night.


This is the pump: https://www.veneersupplies.com/produ...C-240v-AC.html

My table is a version of the Vacupress flip 4x8 table.

I'm also going to pick up some patch kits for the bag to get the pin holes buttoned up.

[Kevin Jenness]

Kevin,

What does your pump pull at the pump inlet when you plug it?

I'm not that impressed that at basically zero volume it can pull a vacuum. I really have tried looking everywhere for a leak and besides a few pin holes that have probably been there forever I can't see any holes near where I put the previous project. Furthermore, just the idea that all I did was open my press up, take out a project, put a new project in and close the table leads me to believe that the pump is the issue.

I can't remember checking the pressure before turning the pump off and opening up the table, but I'm betting if I looked I would have seen the pressure had dropped off during the night.


This is the pump: https://www.veneersupplies.com/produ...C-240v-AC.html

My table is a version of the Vacupress flip 4x8 table.

I'm also going to pick up some patch kits for the bag to get the pin holes buttoned up.

My system shows 24" hg with the line plugged. I could set the switch to shut off at 26-7" but the system would cycle too frequently for my taste.

Pulling a vacuum at very low or no flow is exactly what you want. If the system is tight then even a low flow pump will eventually achieve an acceptable level, but a functional pump can be defeated by a clogged or leaky system. If the vacuum level was decreased at the end of your last session that could be for any of the reasons I suggested. I don't think you should fixate on the pump given that it does show a decent reading when the line at the platen is plugged. You might try to compare the flow rate through the line at the platen connection vs. at the pump inlet.

[andrew whicker]

hmmm

I thought that too (regarding the vacuum pull when it's plugged at the pump).. I keep flipping back and forth between thinking it tells me something and that it doesn't tell me much. It is a 5 cfm pump, so it should be sucking the bag down quickly, within a few minutes.

I did plug the hole into the platten and it read 20 ish. I'm not sure how to measure flow rate without buying a meter. Maybe that's worth it, but it's also just data for the sake of data. I might as well just buy new consumables for the pump. I'd love it if I could plug in a borrowed vacuum pump into the system just to remove the doubt.

The problem is that I really cannot find anything on the bag or the seal. And I have tried over and over again.

I also blew air from my air compressor thru the line between the pump and the platten both ways to try to unclog something and the results didn't change. (pump disconnected).

I'm really lost on this one. it seems like it would have to be a major leak, not a minor leak, to cause such a large drop in performance... I'll keep plugging away at it. The bag's seal was bad when I first got this system and it was very easy to find. I just sprayed water around the perimeter and saw water leaking into the vacuum area.

I really cannot find a leak this time! Trust me, I've tried multiple times with multiple techniques!

[Kevin Jenness]

I'm not sure how to measure flow rate without buying a meter.

If there's a significant line blockage you should be able to sense a difference in flow rate at either end of the hose simply by plugging the line and seeing how long it takes for the gauge to read a certain vacuum level. If you were able to blow compressed air through the line freely then that is probably not the problem. Where is the check valve, though? If it is in the line would that not prevent air flow from the pump end toward the press?

With my 3 or 4 cfm rated pump the gauge will read max vacuum in a second or so when I cap the line with my thumb. If yours takes any significant time to reach 20" then the problem probably is in the pump.

Leaks can be subtle. When I built my frame press I was unable to pull more than a 20" hg vacuum even with double gaskets. I checked every possibility and only found success when I replaced my melamine coated particleboard platen with gloss plastic laminate.

[andrew whicker]

I'm heading back to the shop soon... I'll check some things and get back to this thread.

Thanks for taking the time for responding. I'm tearing my hair out with this one.

[andrew whicker]

So I really pressed my thumb until the pump inlet and got 25. Then I really clogged the table patten hole and got 25.

Then I got tired of screwing around and started dumping water on top of the bag (vs spraying). The corners are leaking! Jeez. Finally.

Not sure how they are leaking yet. I think thru the glue behind the gasket..