Modifying Gorton Radiator Vent Rates

acwagner

Has anyone ever modified a Gorton radiator vent orifice to change the venting rate? I'm wondering if the vent rate is dictated by the visible orifice on the outside or if there is an internal one as well. I suspect it's the outside hole since that would make manufacturing easier.

Basically, I'm looking to make a Gorton "4.5" or a "5.5". I'm considering drilling out the hole slightly larger to get venting rates in between the standard sizes.

retiredguy

If more venting capacity is what you want just add 2 or more vents. If there is a system problem, there may be a better way to fix your problem. Post pictures and explain your desires. there are a lot of good steam guys on this site.

Lard

If you are handy with soldering, the Gorton vents are easily modified or repaired/cleaned (another plus for this style—no crimps!)
The top “cap” seems to have a standard size hole (the same on all vents) machined coaxially, then the rate is determined by the vent hole that intersects it. Increasing rate is easy-just drill the intersecting hole larger. Be sure to have the valve upside-down while drilling to keep the chips out of the valve seat.

Decreasing rate is difficult since you have to avoid getting junk into the valve seat while filling the cross hole. I removed the bimetallic strip/float while doing this to avoid damage and to see that the coaxial hole remained open.

I learned this because I had a few that had failed and had nothing to lose. (It seems like there is residue from the chrome pickling process causing serious corrosion, even in new units). A good polishing of the seat and pintle fixed them, then I modified for a different application.

BobC

A Maid O Mist valve would be easier because the orifice unscrews. If you do drill a Gorton make sure no chips get inside the vent.

Bob

acwagner

@Lard thanks for confirming my theory. Saves me the effort (and cost) of tearing apart multiple to confirm it.

I was planning on taking the smaller vent and making it vent slightly more by drilling out the hole, by the way. I didn't think it was practical to go the other way.

I was also planning on drilling it out upside down like you suggested to prevent the shavings from getting inside. Good tip.

I took one apart as well. I agree they are great vents. All brass construction is probably why they are priced the way they are.

Hap_Hazzard

BobC said:

A Maid O Mist valve would be easier because the orifice unscrews. If you do drill a Gorton make sure no chips get inside the vent.

I'm with Bob on this one. I'd rather screw up a $12.99 MoM vent than a Gorton. For a little extra (~$35) you can even get a vent that comes with five orifices (4, 5, 6, C & D). Great for doing experimental stuff. Once you've figured out the perfect size you can always carefully drill out a Gorton to the same size.

Hap_Hazzard

acwagner said:

I was also planning on drilling it out upside down like you suggested to prevent the shavings from getting inside. Good tip.

If you don't use cutting oil as a matter of course, this is one case where you really should. It makes small chips stick to the drill bit. Also, drill slowly with good pressure so you get one or two long chips instead of a lot of little ones.

ChrisJ

Hap_Hazzard said:

acwagner said:

I was also planning on drilling it out upside down like you suggested to prevent the shavings from getting inside. Good tip.

If you don't use cutting oil as a matter of course, this is one case where you really should. It makes small chips stick to the drill bit. Also, drill slowly with good pressure so you get one or two long chips instead of a lot of little ones.

I drill very fast all of the time and can still get two long chips.
10,000 RPM @ 100 inches per minute into copper for example.

ChrisJ

acwagner said:

@Lard thanks for confirming my theory. Saves me the effort (and cost) of tearing apart multiple to confirm it.

I was planning on taking the smaller vent and making it vent slightly more by drilling out the hole, by the way. I didn't think it was practical to go the other way.

I was also planning on drilling it out upside down like you suggested to prevent the shavings from getting inside. Good tip.

I took one apart as well. I agree they are great vents. All brass construction is probably why they are priced the way they are.

This is the main reason I recommend Gorton and not MOM.

Hap_Hazzard

I took apart a MoM vent. It's the only one I've ever had fail on me. They're all brass except for the bimetal strip, the float and the seal.

ChrisJ

Hap_Hazzard said:

I took apart a MoM vent. It's the only one I've ever had fail on me. They're all brass except for the bimetal strip, the float and the seal.

What's the seal made out of?
Considering it's one of the most important parts of the vent.

acwagner

I haven't worked out the exact approach of how I'm going to bore out the hole yet. The body at the vent "cap" is surprisingly thick--around 0.135". So there's a lot more material than I thought I would have to remove.

It looks like the orifices are:
#4 = 1/32"
#5 = 1/16"
#6 = 3/32"

So, to get a #4.5, for example, I'll probably try enlarging the hole to 3/64".

Any pointers from millwrights out there? Initially I was thinking of doing it using a micro hand drill because the bit will be so small, but I also have a drill press. Given the material thickness, maybe the drill press is a better approach.

I have a several left over Gortons from previous balancing exploits to experiment with. I'm using a Hoffman 1A as a proof of concept on the radiator now to prove the venting between the 4&5 rates gets me what I want.

On the Gorton I took apart looks like both the float and seal are brass.

Hap_Hazzard

ChrisJ said:

What's the seal made out of?

Neoprene.

ChrisJ

acwagner said:

I haven't worked out the exact approach of how I'm going to bore out the hole yet. The body at the vent "cap" is surprisingly thick--around 0.135". So there's a lot more material than I thought I would have to remove.

It looks like the orifices are:
#4 = 1/32"
#5 = 1/16"
#6 = 3/32"

So, to get a #4.5, for example, I'll probably try enlarging the hole to 3/64".

Any pointers from millwrights out there? Initially I was thinking of doing it using a micro hand drill because the bit will be so small, but I also have a drill press. Given the material thickness, maybe the drill press is a better approach.

I have a several left over Gortons from previous balancing exploits to experiment with. I'm using a Hoffman 1A as a proof of concept on the radiator now to prove the venting between the 4&5 rates gets me what I want.

On the Gorton I took apart looks like both the float and seal are brass.

I wouldn't do it by hand, drill press for sure and depending on the size of the current hole a reamer may work better than a drill. Depends on how exact and smooth you want the finished hole.

If you're after "good enough" a drill should do fine especially in brass.

Gsmith

Why not just leave the Hoffman 1A in place?

acwagner

When we originally bought the house I was using Hoffman 1As, but they randomly would get clogged shut. Either with debris, or the surface tension of water droplets inside would hold it shut. I would have to shake them out to open them back up. Those are my two theories at least--I was never really able to verify why they did it. Bottom line, they were not reliable on my system. I switched to Gortons and never had the problem again.

Over the summer I completely repiped my system myself and corrected a bunch of things, so perhaps the Hoffmans will work now. I guess I just like the uniformity of having one type of vent across all the radiators, and I'm already committed to Gortons.

I considered a reamer. I might look more into that since you mentioned it. If I'm going from 2/64" to 3/64" would a reamer be the best option?

ChrisJ

acwagner said:

When we originally bought the house I was using Hoffman 1As, but they randomly would get clogged shut. Either with debris, or the surface tension of water droplets inside would hold it shut. I would have to shake them out to open them back up. Those are my two theories at least--I was never really able to verify why they did it. Bottom line, they were not reliable on my system. I switched to Gortons and never had the problem again.

Over the summer I completely repiped my system myself and corrected a bunch of things, so perhaps the Hoffmans will work now. I guess I just like the uniformity of having one type of vent across all the radiators, and I'm already committed to Gortons.

I considered a reamer. I might look more into that since you mentioned it. If I'm going from 2/64" to 3/64" would a reamer be the best option?

I had the same problem with 1As.
Gortons do it to me as well, but much less. Hoffman 1As it was constant where Gorton's it's more like 2-3 times per season.

acwagner

I'm leaning toward water surface tension vs debris for the cause on the Hoffman 1As. I never opened up a Hoffman but I'm guessing the internal passages are smaller. We both operate at very low pressure, so I think that has something to do with it. It also has that "tongue" that presumably is to help drain water out. Makes me think the design is prone to trapping water under certain conditions.

Hap_Hazzard

acwagner said:

I considered a reamer. I might look more into that since you mentioned it. If I'm going from 2/64" to 3/64" would a reamer be the best option?

I wouldn't recommend it. Reamers make small chips, and a tapered reamer may bottom out before you reach the desired opening.

ChrisJ

acwagner said:

I'm leaning toward water surface tension vs debris for the cause on the Hoffman 1As. I never opened up a Hoffman but I'm guessing the internal passages are smaller. We both operate at very low pressure, so I think that has something to do with it. It also has that "tongue" that presumably is to help drain water out. Makes me think the design is prone to trapping water under certain conditions.

I try to drill holes 3% under the finished size before reaming,
So for 3/64 you'd need to at least drill it bigger before trying to ream.

acwagner

3%-ish under would put it at an odd imperial size bit. I'd probably have to use a metric, something like 1.2 mm. I don't think a smooth finish is that critical. I'll just try drilling it.

Hap_Hazzard

You don't have number sizes?

ChrisJ

Hap_Hazzard said:

You don't have number sizes?

What # drill is 0.04546"?


@acwagner I agree, just drilling is fine.
But if you wanted to ream it, I'd probably use a 1.15mm drill.

Hap_Hazzard

ChrisJ said:

What # drill is 0.04546"?

56½

Seriously though, if you can't settle for .0430 or .0465, I don't think you're going to get much closer with a reamer. How would you even measure it?

ChrisJ

Hap_Hazzard said:

ChrisJ said:

What # drill is 0.04546"?

56½

Seriously though, if you can't settle for .0430 or .0465, I don't think you're going to get much closer with a reamer. How would you even measure it?

I work in a machine shop, so I would use pin gauges.


And I promise a 0465" drill will not drill a 0465" hole.

Hap_Hazzard

ChrisJ said:

And I promise a 0465" drill will not drill a 0465" hole.

And I promise you are not going to end up with a 0.04546" hole.

ChrisJ

> @Hap_Hazzard said:
> (Quote)
> And I promise you are not going to end up with a 0.04546" hole.


Not from just a drill bit no.

gfrbrookline

Why not just use a ventrite #1, especially for the G4? I think if you do anything with the G5 you are going to tun it into a G6.

acwagner

There are certainly other venting options. I may end doing something else, but I like experimenting. Honestly, the venting I have now works fine--this is just fine tuning.

ChrisJ

Hap_Hazzard said:

ChrisJ said:

What # drill is 0.04546"?

56½

Seriously though, if you can't settle for .0430 or .0465, I don't think you're going to get much closer with a reamer. How would you even measure it?

l already told you, you would measure that using pin gauges.

acwagner

Update: I used the drill press. Setup was a little tricky because no side is flat on a Gorton valve. Used a vice with some shims. No problem with shavings going inside.

Gorton 5.5 came out great. I put it on and worked just like I wanted on the radiator.

Gorton 4.5 didn't work because the cheap metric drill bit I have that's listed as 1.2mm is actually closer to 1mm, so it didn't enlarge the hole much.

Hap_Hazzard

3/64" is pretty close to 1.2mm. Did you try that?

acwagner

I happened to have the metric bits from an old project. I ordered a 3/64" bit instead. Just came in today. Drilled it out, but the weather has been too mild to see how the new venting works.

Moral of the story is: verify the actual size of small bits before using them.

Hap_Hazzard

I only have metric bits in .0 and .5 sizes. I figure with the number (and letter) sizes and fractional sizes I pretty much have it covered.

I'm attaching a PDF of a chart I made to hang up by my drill press. It comes in handy sometimes.

acwagner

That's handy--saves me the time of converting and using the calculator.