Questions and Answers about Uniseals.
If you have a question about Uniseals and their use contact me HERE I will add it into the Uniseal FAQ's. I am also interested to hear of how our customers have used Uniseals and could add some photos to the site.

Question
What is a Uniseal?
Answer
Uniseals work like a bulkhead or tank connector but better. Inserted into a hole created in a vessel like a tank or barrel with a holesaw they create a simple and effective liquid tight seal through which a pipe can be inserted directly through the vessel wall into your vessel. Developed with Alcryn by DuPont to solve the problem of pipe to tank seals Uniseals are very effective at creating a liquid tight seal on vessels with complex curved surfaces and reduces costs on what would otherwise be a complex installation process.
Question
What sizes do Uniseals come in?
Answer
Uniseals come in a variety of sizes from 3/16" up to 6" as standard. Designed for normal pressure pipe they can of course fit any pipe of the correct O.D. Measure the Outside Diameter of your pipe and match it to the table on http://www.unisealshop.com/page.cfm?page=3 The table is shown as an image below.
Question
Can I use any size of pipe through the Uniseal?
Answer
Uniseals were designed initially for particular standard sizes of industrial pipe known as Schedule 40 in the United States. In the UK and Europe this is equivalent to our EN1452 standard which is an industrial pipe with a thicker wall than standard household pipe. You can of course use any pipe as long as the Outsdie Diameter (O.D.) of the pipe matches what is required for the Uniseal. The Inside Diameter (I.D.) of the Uniseal should match the Outside Diameter (O.D.) of the pipe to achieve a great seal. However you can use a smaller O.D. pipe through a Uniseal if you only require a light seal which would stop the water although perhaps not under pressure. In most fish pond, aquaponics and hydroponics systems the water is seldom under excess pressure unless it is pumped with a high pressure pump.
Question
What size of Uniseals for 40mm pipe?
Answer
Uniseals are not specifically made for metric pipe sizes. However the U125 Uniseal is made for pipe with an outside diameter of 42 mm (1.65"). Standard thin walled solvent weld (glued) waste pipe as is used in housing is normally 43mm which will fit through the U125 Uniseal although it may be a bit tight. Floplast however make a range of push fit pipe and connectors which is slightly smaller at 41mm O.D. so will fit although not as tightly as a 1 1/4" imperial sized pipe. There is only 1 mm in it! If I was constructing a hydroponics system and wanted to use 40mm pipe with Uniseals then I would consider 40mm Floplast push fit pipe which in the UK is available from Screwfix and B&Q. Another benefit of push fit pipe is push fit elbows etc. so that the whole assembly could be dis-assembled.
Question
Can I get Uniseals in different colours?
Answer
Yes Uniseals are available in different colours and can be ordered by us from the U.S.A. which will take a few weeks to arrive. Until there is a demand for them we only stock black Uniseals.
Question
Are Uniseals expensive?
Answer
Compared to a bulky bulkhead connector you don't seem to get very much for the money. However a lot of time and money went into the development of Alcryn Uniseals and they are guaranteed free of manufacturing defects for 25 years. If it can last for that length of time they actually work out a whole lot cheaper. The mere facts that they are re-usable and won't split or crack makes them a winner. But lets get this even more into perspective, there are less initially expensive hydroponic grommets the difference being that Uniseals installed correctly do not leak! I certainly would not trust some of the grommets I see not to leak on my loft floor/livingroom ceiling.
Question
Uniseals are much cheaper in the U.S.A. why?
Answer
Uniseals are manufactured in the U.S.A. Importing them into the U.K. and the E.U. costs more than you at first realise. Costs include Product costs, Carraige, Customs Duty, Import VAT, fees for charging you the fees and any bank or credit card charges levied for working in a different currency. Prices advertised in the U.S.A. generally do not include any local purchase tax which is different from state to state.
Question
Uniseals on eBay and Amazon can look quite inexpensive?
Answer
Suppliers from around the world can add items for sale on eBay and Amazon. Most often the post and packing charges are huge. There may also be some hidden (to you) charges levied when you import Uniseals as they come through U.K. customs which will amount to 20% for VAT on both the items and postage and a fee to collect the fee. You may also find that your credit card levies a fee for buying in another currency. Here at the Uniseal Shop we supply Uniseals with no hidden costs/charges etc. What you see on our items for sale is the delivered cost and is all you will have to pay.
Question
I ordered Uniseals from another country and didn't have to pay any import tax!
Answer
You may sometimes "get away with it" bear in mind though that you are breaking the law if you purchased from outside of the European Union (inside which the VAT will have been paid) and don't pay VAT when your items are not a "gift". In the eyes of the law this makes you no better than those multinationals who aren't paying their fair share of taxes and people boycotted.
Question
I have seen Uniseals in Retail Packaging, do you sell them like that?
Answer
Yes all of our packs of Uniseals come retail packed with individual bar codes, Uniseal installation instructions etc. Two benefits in this 1 - the retail packs are re-sealable to keep your Uniseals and instructions clean and 2 - I can sell Uniseal packs into Retail outlets (they don't want hundreds of Uniseals just kicking around) and they can hang the packs neatly on wall hooks.
Question
I am a tool retailer selling from my own shop can you supply me with retail packs of Uniseals?
Answer
No problem, I would of course be delighted to sell you Uniseals at wholesale prices. Partly I have got to say as I feel like a bit of a "Uniseal Evangelist" and really want to spread the word.
Question
Can I use a holesaw on my glass aquarium. I want to create an external filter?
Answer
Yes you can cut a good quality hole with a diamond hole cutter. A Uniseal on glass works in exactly the same way as on plastic, GRP etc. Quite an elegant and unobtrusive solution. I am beginning to see a number of Reef Tank enthusiasts using them. I hope to be able to tap into that market as well.
Question
Someone I know said Uniseals leaked!
Answer
The seal provided by the Alcryn in the Uniseal should ensure that "Uniseals don't leak" and tests have been conducted up to 65 P.S.I. without leakage. How it works is that the pipe inserted through the Uniseal exerts outward pressure on the Alcryn which ensures a watertight seal between pipe and Uniseal and also between the Uniseal and vessel. There are two important factors when installing a Uniseal - the quality of the hole and the Outside Diameter of the pipe. Cut your hole with a holesaw and remove any swarf from around the hole with some fine sandpaper. If the holesaw bites in too hard on thin pastic your vessel can buckle and create an elogated eliptical hole so be gentle but firm. If your pipe has too small an Outside Diameter not enough outward pressure will be exerted by the pipe on the Uniseal, so a good tight fit is essential.
Question
What happens when a Uniseal freezes in very cold weather?
Answer
The seal on a Uniseal is created by pressure exerted by the inserted pipe onto the Uniseal and vessel. Undoubtedly the Uniseal will become less pliable in freezing conditions. This should not cause a leak unless there is moisture between the pipe and Uniseal or Uniseal and vessel which itself freezes. A shart tap with a medium sized screwdriver will resolve the problem. Uniseals will stand very cold weather much better than a plastic bulkhead which is apt to split completely.
Question
A bulkhead looks much more substantial than a Uniseal. Can it do the same job?
Answer
Uniseals and bulkheads both have their strong points. A bulkhead will provide some structural strength to a length of pipe entering a rectangular vessel. This however can lead to excessive strain on a bulkhead, particularly inexpensive ones created from second hand PVC. The bulkhead must be positioned directly in line with a pipe run and perpendicular to the vessel. I have seen installations where people have heated their round barrels around their pre-cut hole and quickly fitted the bulkhead to get rid of complex curves and attain the shape. A bit of faffing around there I think.
Question
Can you sell me more than one Uniseal at a time?
Answer
Yes we sell Uniseals in singles, packs of five, packs of ten and packs of twenty. We also sell Uniseals on a wholesale basis in 50 and 100 Uniseal packs. We will sell you any number of Uniseals you desire, there is no maximum. Buying packs of Uniseals saves you money. The more you buy the more you save. Currently we have more than a thousand Uniseals in stock.
Question
Can you sell Uniseals in Europe and the EU?
Answer
Yes we have a section of the website devoted to selling the same Uniseal bulkheads to Europe priced in Euros. The price you see is the price you pay but of course postage into Europe comes at a little more expense than postage to the UK and you may have to pay import taxes levied by your governemt and collected by the carrier. However our Uniseal tank connector offerings into the EU are still very competitive from the investigations I have been able to make. Time will tell. We have also included a page on our web site showing Uniseals which are compatible with metric sized pipes.
Question
Do you sell Uniseals at wholesale prices?
Answer
Yes we are happy to sell Uniseals at wholesale prices. We would normally sell them per 100 of any or mixed sizes. Get in touch for a quote.
Question
Can I use Uniseals with I.B.C. containers which are 1000 litres?
Answer
Yes not a problem. The Uniseals are ideal to connect I.B.C. containers together or simply to insert a pipe into the I.B.C. There is no need to access the other side (inside the I.B.C.) to fit a Uniseal. Simply cut your hole with a holesaw, pop in your Uniseal and push the pipe through from the outside. Much simpler than fitting nuts and bolts through a large tank connector or trying to stop the inside of your tank connecter spinning when you try to tighten it.
Uniseals connecting IBC containers
Question
Are Uniseals any good for hydroponics?
Answer
Ideal. They are similar to top hat grommets but have a better design that means you can get a waterproof seal on your system. They are particularly ideal for Dutch Bucket systems for the exit from the bucket and the entry to the drain pipe as they can be dismantled and reused again. We sell the Uniseal product under the name Hydroponic Grommets on our web site and eBay.
Question
Can I join one pipe to another using a Uniseal?
Answer
This is an ideal scenario to show how versatile uniseals are, you could easily join a 2 inch pipe into say a 4 inch pipe at 90° and tap into any water flow in the 4 inch pipe. The possibilities are endless for water and low pressure air. The Uniseal will take on the rounded shape of the larger pipe of any size something not possible with bulkhead tank connectors.
One inch pressure pipe connected through Uniseal to 4" pipe.	Connecting 2" pressure pipe to 4" drain pipe.	Two inch pressure pipe connected to four inch drain pipe underground.
Question
I cut holes in two plastic barrels at slightly different heights and my pipe has gone into my water barrels through the Uniseals at an angle and is not straight. Is this OK?
Answer
Yes this is fine, your Uniseal will still work perfectly up to an angle of around 20°.
Question
Do you need any tools to insert a Uniseal into a hole, I have heard it can be difficult?
Answer
Yes it can be difficult particularly with the large 4" Uniseal, however if you put a 45° chamfer on the end of the pipe taking away all of the flat cut end and lubricate the Uniseal and the pipe before insertion with dish washing liquid you will find it goes in with less difficulty. Silicon pipe lubricant as used by plumbers is an even better lubricating solution. Some people use a block of wood on the end of the pipe to get more purchase when pushing. With really large pipes it is worthwhile using a ratchet strap around your vessel and along the length of the pipe to slowly pull the pipe into the Uniseal. I have added some links to Uniseal Installation tips found on YouTube.
Question
Can I cut the hole for the Uniseal without using a hole saw?
Answer
Yes of course you can but I wouldn't. The quality of the hole plays a significant part in achieving a good seal. The hole should be the correct size and any bits of swarf should be cleaned off before insertion of the Uniseal.
Question
Uniseals are all inch (Imperial) sizes but I can only find metric hole cutters?
Answer
That is OK just pick the hole cutter that is closest in mm to the Imperial size you require. Good quality (and expensive unfortunately) hole saws all have metric equivalents of the Imperial size. A good hole saw manufacturer is Starrett who actually come from the U.S.A. so their hole saws though marked in metric sizes for the E.U. market are of course produced as Imperial sizes for the U.S. market. We have also introduced a range of suitable good quality Uniseal holesaws here at Seals4u to save our customers having to track them down.
Question
I have thick sided plastic containers that I want to use a Uniseal on. What is the thickest that a Uniseal can go through?
Answer
A Uniseal generally can be used up to a wall thickness on your containers of 3/8" which is quite a thick wall. Plastic walled vessels are normally thinner than 3/8". The Largest Uniseals can be used up to 1/2" wall thickness.
Question
I found a hole saw set on eBay that came from China will that be any good to make my holes for my Uniseals?
Answer
An inexpensive hole saw should be OK to create your holes in plastic or plywood. Creating a decent hole in aluminium or mild steel would probably be impossible. The main criteria in creating your hole is that it is a good clean hole with no swarf. A really cheap hole saw may do the job just fine as long as the teeth on the holesaw remain sharp. On a cost per hole basis this would really keep the price down. There is every likelihood that you will not be able to cut dozens of holes though. Please remember when using a holesaw not to run the saw too quickly, the slower the better.
Question
Will my holesaw cut through fibre glass?
Answer
Depends on the quality of your hole saw and the toughness of the glass fibre. The holesaws in the Uniseal Holesaw Kit that we sell from Seals4u are good quality and are up to creating holes in mild steel.
Question
Where do you get your Uniseals?
Answer
I import the Uniseals in bulk direct for the manufacturer in the U.S.A. with whom we have a business to business relationship. When I first started this business I imported from the Uniseal Warehouse but that was too expensive. We have over a thousand in stock. I am trying to "pile 'em high and sell 'em cheap" and I do sell them cheaper than any other UK or EU business. If you want to try importing Uniseals for yourself you could try the Uniseal Warehouse in the U.S.A., some people like to learn lessons the hard way!
Question
Do you sell Uniseals outside of the UK for example will you sell Uniseals in Europe?
Answer
Yes we have customers throughout the globe. Our pricing includes free postage and packing in the UK. It is not free of course but included in the Uniseal price in the UK. When we export Uniseals to Europe or other parts we deduct the cost of the UK postage and add on the cost to Europe, Asia or wherever. We do not try to make any profit on postage and packing. By doing this we keep down the overall cost of Uniseals sent around the world for our customers. So if you would like Uniseals in Europe, Uniseals in Asia, Uniseals in Africa or wherever just contact us. We have even sent Uniseals to the USA.
Question
Who sells Metric Uniseals
Answer
The short answer is nobody! Uniseals are produced only by one manufacturer in the U.S.A. They are all produced in Imperial sizes for Schedule 40 pipe which is an industrial standard for thick walled or pressure pipe. This does not mean that metric sized pipe will not fit and there are many equivalent sizes that do. The important measurement is the Outside Diameter of the pipe (whether it is thin or thick walled). One example it the U125 Uniseal which is a good fit for some 40mm pipe and is widely used in Aquaponics and Hydroponics. There is a link on the menu of our site for Metric Uniseals which explains more and shows equivalent metric sizes. We have a sizes chart for metric uniseals that is shown below.